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Agricultural  Experiment  Station. 

URBANA,  JUNE,   1899. 


BULLETIN  No.   55. 


LVIFROVEMENT  IN  THE  CHEMICAL  COMPOSlTIOiN  OF  THE 

CORN  KERNEL 


IxNTRODUCTION. 


The  many  different  uses  which  are  made  of  corn  and  the  enormous 
value  of  the  crop  to  the  United  States  in  general,  and  to  the  state  of 
Illinois  in  particular,  may  certainly  be  deemed  sufficient  reason  for 
investigating  the  possibility  of  making  improvements  in  the  chemical 
composition  of  this  important  grain.  The  nature  of  any  desired  im- 
provement will,  of  course,  depend  upon  the  use  which  is  to  be  made  of 
the  crop  produced.  For  example,  if  corn  is  grown  for  the  manufacture 
of  starch,  glucose-sugar,  syrup,  or  alcohol,  it  is  desirable  that  the  grain 
contain  a  high  percentage  of  carbohydrates,  and  that  the  percentages  of 
its  other  chief  constituents,  protein  and  fat,  should  be  reduced  as  much 
as  possible.  If  corn  is  to  be  used  as  feed  for  growing  animals  or  man- 
ufactured into  cornflour  for  human  food,  a  higher  percentage  of  protein 
will  certainly  increase  its  value.  If  it  is  to  be  used  chiefly  for  fattening 
stock,  perhaps  an  increased  percentage  of  fat  would  be  an  improvement. 

That  the  chemical  composition  of  corn  can  be  changed  seems  rea- 
sonably probable  from  the  changes  which  have  been  produced  in  some 

other  plants, — natably  in  the  sugar  beet. 

205 


2o6  BULLETIN    NO.     55.  \^  J  title, 

Preliminary  Stl'i>v. — Before  the  work-  reported  in  this  bulletin 
could  be  begun,  it  was  necessary  to  make  a  chemical  study  of  the  corn 
plant,  and  to  devise  methods  for  conducting  experiments  with  the  object 
of  improving  the  composition  of  the  grain.  It  is  known  that  the  min- 
eral content  of  plants  can  be  changed  to  some  extent  by  the  addition  to 
the  soil  of  mineral  materials  in  a  form  readily  available  to  the  plant, 
but  that  the  temporary  change  thus  effected  would  have  any  appreciable 
hereditary  tendency  seems  very  unlikely.  The  method  of  procedure 
which  seemed  most  promising  is  based  upon  the  common  method  of 
making  improvement  in  animals,  namely,  selecting  the  best  examples  of 
the  desired  type  and  breeding  successively  and  under  the  best  conditions 
from  that  stock,  retaining  from  each  generation  only  the  highest  types 
obtained.  This  is  practically  the  method  by  which  the  sugar  content 
of  certain  varieties  of  beets  has  been  increased  from  less  than  five  per 
cent,  to  twelve  or  even  to  sixteen  per  cent.  A  small  portion  of  a  beet 
is  analyzed  and,  if  it  is  found  to  be  sufficiently  rich  in  sugar,  the  beet  is 
then  set  out  as  a  "mother,"  or  seed,  beet.  From  the  seed  produced 
beets  are  grown  and  another  selection  of  seed  beets  is  made  on  the  basis 
of  their  sugar  content.  But  the  kernel  of  corn  is  not  sufficient  in  quantity 
to  make  a  complete  chemical  analysis  by  any  practical  method,  and  cer- 
tainly the  same  kernel  could  not  be  used  for  analysis  and  also  for  seed. 

Early  in  the  year  1896  the  writer  began  a  special  study  of  the 
chemistry  of  corn.  Although,  in  the  latter  part  of  that  year,  all  of  the 
analytical  records  of  the  work  were  destroyed  by  fire,  some  valuable 
knowledge  of  the  subject  had  been  obtained.  Among  the  important 
facts  which  the  results  obtained  had  indicated  were: 

1.  That  the  ear  of  corn  is  approximately  uniform  throughout  in 
the  chemical  composition  of  its  kernels. 

2.  That  there  is  a  wide  variation  in  the  chemical  composition  of 
different  ears  of  the  same  variety  of  corn. 

That  these  conclusions  are  correct  has  been  fully  shown  by  some 
more  recent  work  of  which  the  data  have  already  been  published  in 
detail  in  Bulletin  No.  53  (see  pages  150  to  157). 

Plan  of  Experiments. — The  uniformity  of  the  individual  ear  of 
corn  makes  it  possible  to  determine  very  approximately  the  composition 
of  the  grain  by  analyzing  a  sample  consisting  of  a  few  rows  of  kernels. 
The  remainder  of  the  kernels  on  the  ear  may  then  be  planted  if  desired. 
The  wide  variation  in  composition  between  different  ears  is  a  very  im- 
portant factor  in  the  work  of  selecting  seed,  as  a  starting  point  is  thus 
furnished  in  each  of  the  several  lines  of  desired  improvement.  The 
general  plan  of  the  experiments  to  improve  the  composition  of  corn  was 
to  make   analyses   of  samples   from   a   large   number  of  ears,  select  for 


1899]  CHEMISTRY    OF    THE    CORN    KERNEL.  207 

seed  those  ears  which  were  found  to  contain  a  high  percentage  of  a 
desired  constituent,  plant  in  an  isolated  field  (to  avoid  cross  fertiliza- 
tion from  other  corn),  and  grow  the  crop  under  as  good  field  conditions 
as  possible.  From  the  crop  obtained  a  large  number  of  ears  are 
selected,  and  samples  of  each  ear  are  analyzed,  seed  being  taken,  as 
before,  from  those  ears  which  are  found  to  be  highest  in  the  percentage 
of  the  constituent  which  it  is  desired  to  increase.  Each  year  this  pro- 
cess is  repeated. 

While  it  may  require  ten  or  twenty  years'  work  to  enable  one  to 
form  a  very  definite  opinion  as  to  the  extent  to  which  it  is  possible  to 
influence  the  chemical  composition  of  corn,  it  is  believed  that  the  data 
and  results  thus  far  obtained  may  be  of  practical  and  scientific  interest. 

General  Explanations. — All  work  reported  in  this  bulletin  was 
done  upon  a  single  variety  of  corn,  commonly  known  as  Burr's  White. 
It  has  been  grown  for  several  years  by  this  Station  with  precautions  to 
keep  the  variety  pure  and  distinct. 

The  analytical  methods  employed  have  been  described  in  detail  in 
Bulletins  43  and  53  of  this  Station.  They  are  based  upon  the  methods 
of  the  Association  of  Ofticial  Agricultural  Chemists. 

By  the  term  ash  is  meant  the  mineral  matter  which  remains  after 
the  organic  matter  is  burned. 

Proteifi  consists  of  the  nitrogenous  organic  matter.  It  is  the  chief 
constituent  necessary  to  the  growth  and  repair  of  the  animal  body. 

The/a^  is  the  material  extracted  from  corn  by  ether.  It  is  practi- 
cally pure  corn  oil. 

The  carbohydrates  consist  chiefly  of  starch,  but  include  also  the 
small  amounts  of  other  allied  substances  found  in  corn,  as  sugar,  fiber, 
and  pentosans. 

Unless  otherwise  stated,  all  results  are  reported  on  the  basis  of  dry 
matter,  or  water-free  substance. 

For  more  complete  explanations  of  technical  terms,  or  information 
concerning  the  uses  of  food  constituents,  the  reader  is  referred  to  the 
appendix  to  Bulletin  No.  43. 

SELECTION  OF  SEED  CORN  BY  ANALYSIS. 

From  the  1896  crop  of  Burr's  White  corn  grown  upon  the  Experi- 
ment Station  farm,  two  bushels  (163  ears)  of  good,  sound  ear  corn 
suitable  for  seed  were  taken.  From  each  ear  a  sample  consisting  of 
three  rows  of  kernels,  lengthwise  of  the  ear,  was  taken  for  analysis. 
The  data  obtained  from  the  analysis  of  the  one  hundred  sixty-three 
samples  appear  in  Table  i. 


2o8  BULLETIN    NO.    55.  \_Jltne 

TABLE  I.    Composition  of  Corn  from  One  Hundred  Sixty-three  Different  Ears. 


Corn   . 
»»     A 

sh. 

Protein. 

Fat. 

Carbo- 

Corn  . 

XT          *> 

sh. 

Protein. 

Fat. 

Carbo- 

No. 

.70 

hydrates. 

No. 

hydrates. 

76   I 

10.05 

4-77 

83  48 

131   I 

.47 

10.49 

4.86 

83  18 

77   I 

•45 

10.42 

5-24 

82.89 

132   I 

•  55 

II. 13 

4 

•  55 

82.77 

78   I 

•55 

11.00 

4.90 

82.55 

133   I 

.39 

11.13 

4 

10 

83.38 

79   I 

.62 

10.89 

4.88 

82.61 

134   I 

•  30 

10.85 

4 

45 

83.40 

80   I 

•63 

11.50 

4.58 

82.29 

135   I 

.37 

11.29 

4 

53 

82.81 

81   I 

.47 

11.49 

4.26 

82.78 

136   I 

59 

11.43 

5 

10 

81.88 

82   I 

•39 

11.78 

4-83 

82.00 

137   I 

47 

II. 61 

4 

41 

82.51 

83   I 

17 

9.08 

4-05 

85.70 

138   I 

36 

11.36 

4 

53 

82.75 

84   I 

•  51 

12.79 

4^25 

81.45 

139   I 

57 

9.81 

5 

23 

83.39 

85   I 

46 

11.76 

4-94 

81.84 

140   1 

34 

10.53 

4 

18 

83.95 

86   I 

50 

12.07 

4.61 

81.82 

141    1 

45 

12.42 

4 

51 

81.62 

87   I 

59 

12.40 

4^74 

81.27 

142   1 

37 

9.31 

4 

82 

84.50 

88    I 

35 

9-34 

4.84 

84.47 

143   I 

29 

11.33 

4 

49 

82.89 

89    I 

61 

10.71 

4.70 

82.98 

144   1 

42 

"•39 

4 

99 

82.20 

90    I 

55 

9.90 

4-97 

83^58 

145   I 

45 

8.25 

4 

81 

85.49 

91    I 

56 

10.68 

4.91 

82.85 

146   1 

47 

11.29 

4 

83 

82.41 

92    I 

46 

12.96 

3^97 

81.61 

147   I 

26 

12.21 

4 

49 

82.04 

93    I 

48 

11.80 

4.80 

81.92 

148   1 

54 

11.94 

4 

74 

81.78 

94    I 

74 

11.89 

4-55 

81.82 

149   I 

36 

11.29 

4 

08 

83.27 

95    I 

55 

10.49 

5-51 

82.45 

150   I 

44 

11.71 

4 

03 

82.82 

96    I 

60 

11.10 

4.38 

82.92 

151   I 

40 

9^31 

4- 

96 

84.33 

97   I 

59 

11.84 

4.96 

81.61 

152   I 

41 

11.90 

4^ 

09 

82.60 

98   I 

39 

10.23 

5-51 

82.87 

153   I 

35 

12.51 

5- 

19 

80.95 

99   I 

42 

8.40 

4.91 

85.27 

154   I- 

42 

11.13 

5 

02 

82.43 

100   I 

65 

12.28 

4.76 

81.31 

155   I. 

44 

11.05 

4. 

53 

82.98 

lOI     I 

30 

10.08 

4.86 

83.76 

156   1. 

39 

11.74 

4- 

14 

82.73 

102    I 

49 

11.83 

4-51 

82.17 

157   I. 

46 

10.02 

4- 

88 

83.64 

103    I 

44 

11.25 

4.78 

82.53 

158   1. 

45 

10.66 

4. 

51 

83.38 

104    I 

54 

11.82 

4-43 

82.21 

159   I. 

48 

"•53 

4 

65 

82.34 

105    I 

37 

12.36 

4.84 

81.43 

160   I. 

43 

11.50 

4- 

83 

82.24 

106    I 

33 

II. 15 

5-21 

82.31 

161    1. 

47 

11.11 

4- 

93 

82.49 

107    I. 

33 

9.47 

4-97 

84.23 

162   1 

48 

12.09 

5. 

61 

80.82 

108    I 

30 

11.04 

4.67 

82.99 

163   I. 

29 

10.78 

5- 

09 

82.84 

109    I. 

45 

10.82 

5^65 

82.08 

164   1 

30 

9.36 

4- 

34 

85.00 

no    I. 

60 

12.81 

5.21 

80.38 

165   I. 

47 

10.50 

4- 

75 

83.28 

Ill   I. 

31 

10.76 

4-13 

83.80 

166   I 

65 

11.29 

3 

84 

83.22 

112     I. 

26 

10.48 

4-54 

83.72 

167   1 

37 

9.58 

4- 

72 

84.33 

113     I. 

10 

9.30 

4-38 

85.22 

168   1 

49 

10.94 

4 

34 

83.23 

114     I 

33 

9.12 

4.10 

85^45 

169   1. 

60 

11.79 

4- 

22 

82.39 

115     I 

29 

10.41 

4^17 

84.13 

170   I 

36 

11.06 

4 

39 

83.19 

116     I. 

10 

8.38 

4.88 

85.64 

171    I. 

44 

11.18 

5- 

75 

81.63 

117     I. 

42 

9-95 

4-23 

84.40 

172   1 

45 

12.28 

3 

99 

82.28 

118     I. 

44 

11.40 

5.02 

82.14 

173   I. 

39 

10.14 

4 

35 

84.12 

119     I 

55 

12.38 

4.62 

81.45 

174   1. 

30 

10.19 

5 

22 

83.29 

120     I 

39 

9.97 

4.42 

84.22 

175   I. 

40 

12.68 

5 

29 

80.63 

121     I. 

36 

10.09 

4.82 

83^73 

176   I. 

37 

9.86 

4 

73 

84.04 

122     I. 

36 

10.31 

5.25 

83.08 

177   I. 

48 

13.06 

4 

93 

80.53 

123     I. 

34 

9,68 

4.01 

84.97 

178   1 

37 

10.93 

4 

76 

82.94 

124     I 

44 

11.87 

4.61 

82.08 

179   1 

32 

11.87 

5 

03 

81.78 

125     I 

34 

10.73 

4^53 

83.40 

180   1. 

39 

11.27 

4 

55 

82.79 

126     I. 

49 

13.87 

5^72 

78.92 

i8i    I 

47 

9.66 

4 

21 

84.66 

127     I. 

43 

"•53 

4^31 

82.73 

182    1 

37 

10.97 

3 

94 

83.72 

128     I. 

33 

11.64 

4-57 

82.46 

183    I 

54 

10.32 

5 

46 

82.68 

129     I. 

36 

11.25 

4.16 

83.23 

184    1 

44 

10.68 

4 

89 

82.99 

130     I. 

35 

11.86 

5^oi 

81.78 

185    1 

42 

9.33 

4 

49 

84.76 

1899.] 


CHEMISTRY  OF  THE  CORN  KERNEL. 


209 


TABLE  I.     Coyittnued. 


Corn 

No. 

Ash. 

Protein. 

Fat. 

Carbo- 
hydrates. 

Corn   . 
No.  ^ 

sh. 

Protein. 

Fat. 

Carbo- 
hydrates. 

186 

1.48 

10.78 

4-74 

83.00 

213   I. 

53 

12.40 

4.75 

81.32 

187 

1.28 

10.49 

4-44 

83.79 

214   I 

58 

10.22 

4-43 

83.77 

188 

1-53 

13.10 

5.51 

79.86 

215   I 

45 

9.22 

4.60 

84.73 

189 

1.32 

9.58 

5.63 

83.47 

216   I 

42 

10.27 

4.35 

83.96 

190 

1-25 

11.50 

4-95 

82.30 

217   I 

32 

9.39 

4.83 

84.46 

191 

1.29 

II. 19 

4.31 

83.21 

218   I 

40 

9.74 

4.71 

84.15 

192 

1. 51 

11.49 

4.07 

82.93 

219   I 

37 

9.92 

4.32 

84.39 

193 

1.36 

9.47 

4.51 

84.66 

220   I 

43 

9.63 

5.23 

83.71 

194 

1.50 

11.47 

4.65 

82.38 

221   I 

32 

10.33 

5.01 

83.34 

195 

1-54 

11.09 

4-37 

83.00 

222   I 

41 

12.34 

4.57 

81.68 

196 

1.30 

9-44 

3.95 

85.31 

223   I 

49 

10.58 

4.64 

83.29 

197 

1.26 

II  .20 

4.46 

83.08 

224   I 

52 

11.36 

4.63 

82.49 

198 

1.44 

10.23 

4.53 

83.80 

225   I 

33 

9.15 

4.55 

84.97 

199 

1.29 

10.64 

4.67 

83.40 

226   I 

.36 

10.31 

5.08 

83.25 

200 

1-39 

10.13 

4.84 

83.64 

227   I 

46 

12.63 

5.15 

80.76 

201 

1.38 

9.64 

5.22 

83.76 

228   I 

41 

12.16 

4.12 

82.31 

202 

1-39 

II  .26 

4.96 

82.39 

229   I 

.36 

11.04 

4.52 

83.08 

203 

1.26 

10.48 

4.59 

83.67 

230   I 

.43 

12.10 

4.29 

82.18 

204 

1.66 

12.57 

4.82 

80.95 

231   I 

.33 

10.95 

4.60 

83.12 

205 

1.46 

10.71 

5.36 

82.47 

232   I 

•52 

12.76 

4.10 

81.62 

206 

1.34 

10.27 

4.65 

83.74 

233   I 

.40 

9.75 

4.14 

84.71 

207 

1.25 

11.09 

4.27 

83.39 

234   I 

•39 

10.78 

4.76 

83.07 

208 

1.48 

12.05 

4.78 

81.69 

235   I 

.58 

9.97 

5.27 

83.18 

209 

1.48 

10.22 

4-30 

84.00 

236   I 

.40 

10. 18 

6.02 

82.40 

210 

1-45 

II. 16 

4-75 

82.64 

237   I 

.47 

1 1. 16 

5.13 

82.24 

211 

1.48 

10.44 

4.21 

83.87 

238   I 

.60 

11.42 

5.20 

81.78 

212 

1.27 

9.75 

4.12 

84.86 

Plans  were  made  to  carry  on  four  separate  experiments  to  change 
the  chemical  composition  of  corn:  i.  To  increase  the  protein  con- 
tent. 2.  To  decrease  the  protein  content.  3.  To  increase  the  fat  content. 
4.  To  decrease  the  fat  content.  It  is  of  course  manifest  that,  if  the 
percentages  of  protein  and  fat  are  increased,  the  percentage  of  carbohy- 
drates is  decreased,  and  vice  versa.  From  the  lot  of  one  hundred  sixty- 
three  ears,  four  different  sets  of  seed  corn  were  selected  on  the  basis  of 
chemical  composition. 

1.  A  set  of  twenty-four  ears  whose  percentage  of  protein  was  com- 
paratively high. 

2.  A  set  of  twelve  ears  each  of  which  contained  a  low  percentage 
of  protein. 

3.  A  set  of  twenty-four  ears  high  in  fat  content. 

4.  A  set  of  twelve  ears  low  in  fat  content. 


2IO  BULLETIN    NO.    55.  \^/une, 

OUTLINE  OF  EXPERIMENTS. 

In  the  spring  of  1897  the  four  sets  of  corn  which  had  been  selected 
were  planted  on  four  different  fields,  or  plots,  each  of  which  was  fairly- 
well  isolated  from  other  corn  fields  in  order  to  avoid  cross  fertilization 
by  corn  of  different  chemical  composition.  For  convenience  these 
four  plots  are  called:  i.  High-protein  plot.  2.  Low-protein  plot. 
3.  High-fat  plot.  4.  Low-fat  plot.  Invariably  the  seed  planted  in 
each  row  was  all  taken  from  a  single  ear;  so  that  the  high-protein  plot, 
for  example,  contained  twenty-four  rows  planted  with  seed  from  the 
twenty-four  ears  selected  for  that  purpose. 

In  the  high-protein  and  high-fat  plots  the  seed  containing  the  very 
highest  percentage  of  the  desired  constituent  was  planted  in  the  middle 
rows,  the  remainder  of  the  seed  being  planted  in  approximately  uniform 
gradation  to  either  side.  In  the  low-protein  and  low-fat  plots  the  seed 
containing  the  very  lowest  percentages  of  protein  and  fat,  respectively, 
was  planted  in  the  middle  rows.  This  arrangement  may  be  clearly  seen 
by  referring  to  the  tables. 

By  planting  plots  of  both  high-protein  and  low-protein  corn,  or  of 
both  high-fat  and  low-fat  corn,  results  may  be  obtained  which  show  the 
influence  of  selected  seed,  as  independent  and  distinguishable  from  the 
effects  due  to  the  influence  of  the  season. 

The  plots  were  given  ordinary  cultivation,  and  a  good  crop  of  corn 
was  grown  on  each.  When  the  corn  was  harvested  a  set  of  ten  good  ears 
was  selected  from  each  row,  excepting  from  some  outer  rows.  From 
some  of  the  middle  rows  duplicate  sets  of  ten  ears  each  were  taken  from 
the  same  row,  as  will  be  seen  from  the  tables,  the  analytical  data  from 
such  rows  being  given  in  duplicate  in  all  cases.  Two  rows  of  kernels 
(lengthwise  of  the  ear)  were  taken  from  each  of  the  ten  ears  and  mixed 
to  form  a  composite  sample  to  represent  the  good  corn  grown  on 
each  row. 

EXPERIMENTS  TO  INFLUENCE  THE   PROTEIN  CONTENT 

OF  CORN. 

The  results  from  the  experiments  to  change  the  percentage  of  pro- 
tein in  corn  will  be  first  considered.  The  tables  are  arranged  to  show 
the  percentage  of  protein  in  the  dry  matter  of  the  seed  planted  and  the 
crop  produced.  For  reference,  the  Station  laboratory  serial  numbers  of 
all  samples  analyzed  are  also  given  (see  Tables  2  and  3). 


1899-] 


CHEMISTRY  OK  THE  CORN  KERNEL. 


211 


TABLE  2.  — Protein  in  Corn  Planted  and  Harvested  on  High-protein  Plot 

IN  1897. 


Plot 

Corn 

planted. 

Corn 

aarvested 

Plot 
row 
No. 

Corn 

planted 

Corn 

larvested. 

row 

No. 

Corn 

Protein, 

Corn 

Protein, 

Corn 

Protein, 

Corn 

Protein, 

No. 

per  cent. 

No. 

per  cent. 
9.61 

No. 

per  cent 

No. 
j  345 

per  cent. 

I 

94 

11.89 

270 

14 

177 

13.06 

10.89 

2 

86 

12.07 

275 

11.07 

1  350 

10.67 

3 

230 

12.10 

280 

10.94 

188 

13.10 

\  355 

10.34 

4 

213 

12.40 

285 

11.48 

15 

(  360 

11.48 

5 

100 

12.28 

290 

10.85 

16 

232 

12.76 

365 

11.05 

6 

119 

12.38 

295 

11.64 

17 

87 

12.40 

370 

10.75 

7 

227 

12.63 

300 

11.46 

18 

204 

12.57 

375 

10.86 

8 

153 

12.51 

305 

11.57 

19 

105 

12.36 

380 

11.07 

9 

175 

12.68 

310 

11.17 

20 

141 

12.42 

385 

10.88 

10 

84 

12.79 

315 

11.14 

21 

172 

12.28 

390 

11.73 

u 

no 

12.81 

^20 

11.16 

22 

222 

12.34 

395 

10.76 

12 

126 

92 

13.87 
12.96 

j  325 
1  330 
j335 
/  340 

11.60 
11.31 
11.07 
11.44 

23 

24 

147 
208 

12.21 
12.05 

400 
405 

11.30 
11.53 

13 

Plot  averages 

12.54 

11.10 

TABLE  3  — Protein  in  Corn  Planted  and  Harvested  on  Low-protein  Plot 

IN  1897. 


Plot 

Corn 
Corn 

planted. 
Protein, 

Corn  harvested. 

Plot 
row 
No. 

Corn 
Corn 

planted. 
Protein, 

Corn  harvested. 

row 

No. 

Corn 

Protein, 

Corn 

Protein, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

I 
2 

151 
114 

9.31 
9.12 

410 

10.55 

7 

99 

8.40 

i  440 
1  445 

10.36 
10.20 

3 

81 

9.08 

415 

10.89 

8 

215 

9.22 

450 

9.89 

4 

225 

9.15 

420 

10.26 

9 

185 

9.33 

455 

10.24 

5 

116 

8.38 

425 

10.10 

10 

164 

9.36 

460 

11.20 

6 

145 

8.25 

J430 
1  435 

10.73 
9.90 

II 
12 

113 
193 

9.30 
9.47 

465 

12.24 

Plot  averages 

9.03 

10.55 

It  is  observed  that  the  average  composition  of  the  corn  from  the 
high-protein  plot  shows  a  protein  content  of  11. 10  per  cent.;  while 
10.55  ^s  the  average  percentage  of  protein  in  the  corn  from  the  low- 
protein  plot,  indicating  that  the  difference,  .55  per  cent.,  may  be  ascribed 
to  the  influence  of  the  seed  selection.  On  account  of  the  plan,  or 
order,  in  which  the  seed  corn  was  arranged  in  the  plots,  that  is,  with 
the  corn  of  highest  protein  content  in  the  central  rows  of  the  high-pro- 
tein plot,  and  the  corn  of  lowest  protein  content  in  the  central  rows  of 
the  low-protein  plot,  we  might  expect  to  find  a  somewhat  wider  average 
difference  in  protein  content  if  we  consider  only  the  corn  grown  on  the 
central  half  of  each  plot.  From  rows  7  to  18  of  the  high-protein  plot 
we  find  the  average  protein  cofitent  of  the  corn  produced  to  be  11. 12 
per    cent.,   while    10.21   is  the  average   percentage    of    protein   in   the 


212 


BULLETIN    NO.    55.  \^June, 


corn  from  rows  4  to  9  of  the  low-protein  plot,  thus  showing  an  average 
difference  of  .91  per  cent. 

From  each  set  of  ten  ears  from  the  1897  crop,  four  of  those  which 
appeared  most  suitable  for  seed  corn  were  reserved  for  further  use. 
These  amounted  to  one  hundred  twelve  ears  from  the  high-protein  plot 
and  forty-eight  ears  from  the  low-protein  plot.  From  each  of  these 
ears  a  sample  consisting  of  three  or  four  rows  of  kernels  was  taken  for 
analysis,  only  protein  and  dry  matter  being  determined.  Tables  4  and 
5  give  the  percentage  of  protein  in  the  dry  matter  of  these  samples. 
The  laboratory  numbers  of  these  samples  of  single  ears  afford  ready 
reference  to  the  row  of  the  plot  in  which  they  grew  and  to  the  seed 
from  which  they  were  grown.  Thus,  to  each  four  ears  are  given  the 
four  numbers  immediately  following  the  number  given  to  the  com- 
posite sample  of  ten  ears  from  the  same  row.  For  example,  the 
composite  sample  from  ten  ears  from  row  i,  high-protein  plot,  1897, 
is  given  No.  270,  as  will  be  seen  by  reference  to  Table  2;  and  the 
four  samples  of  single  ears  from  the  same  row  are  numbered  271, 
272,  273,  and  274  (Table  4).  Table  2  also  shows  that  these  ears  grew 
from  corn  No.  94,  which  contained  11.89  P^^  cent,  of  protein  in  the 
dry  matter;  so  that  the  complete  pedigree  of  each  ear  is  kept  from 
the  beginning  of  these  experiments. 

While,  as  has  already  been  shown,  the  protein  content  of  corn 
from  the  high-protein  plot  averages  higher  than  that  from  the  low-pro- 
tein plot,  attention  is  called  to  the  wide  variation  in  the  percentage  of 
protein  in  corn  from  different  ears  grown  in  a  single  season,  in  the  same 
plot  of  ground,  and  from  seed  of  nearly  uniform  protein  content.  This 
is  especially  marked  in  the  ears  from  the  low-protein  plot  (Table  5). 
For  example,  corn  No.  458  contains  8.22  per  cent,  of  protein  and  grew 
from  seed  No.  185  which  contained  9.33  per  cent,  of  protein;  while  corn 
No.  466  contains  i3.98'per  cent,  of  protein  and  grew  from  seed  No.  113 
whose  protein  content  was  9.30  per  cent. 

Of  course  the  pedigree  of  the  individual  ears  used  for  seed  in  1897 
was  not  known,  and  possibly  some  variations  may  be  due  to  hereditary 
influences,  but  it  seems  probable  that  the  wide  variations  are  caused 
principally  by  local  differences  of  soil  conditions.  Some  efforts  to 
obviate  this  difficulty  are  discussed  farther  on. 

In  order  to  retain  hereditary  influences  the  seed  for  the  high-protein 
plot  for  1898  was  all  selected  from  corn  which  grew  from  seed  of  high 
protein  content  the  previous  year.  On  this  account  corn  with  high 
protein  content  from  the  low-protein  plot  was  rejected  for  seed.  Like- 
wise seed  for  1898  for  the  low-protein  plot  was  selected  only  from  corn 
which  grew  upon  that  plot  in  1897. 


1899.] 


CHEMISTRY    OF    THE    CORN    KERNEL. 


213 


TABLE  4. — Protein  in  Samples  of  one  hundred  twelve  Ears  of  Corn  grown  on 

High-protein  Plot  in  1897. 


Corn 
No. 


271 
272 

273 
274 

276 
277 
278 
279 

281 
282 
283 
284 

286 
287 
288 
289 

291 
292 

293 
294 

296 
297 
298 
299 

301 
302 
303 
304 


Protein, 
per  cent. 


8.82 

8.42 

11.60 

8.34 

12.83 

10.46 

9.95 

10.96 

12.62 

10.43 

9.87 

11.58 

10.97 
11.08 
10.23 
12.99 

11.52 
10.44 
11.92 
11.25 

11.11 
12.07 
13.58 
11.68 

10.80 
12.26 
11.20 
11.97 


Corn 

No. 


306 

307 
308 

309 

3" 
312 

313 
314 

316 
317 
318 
319 

321 
322 

323 
324 

326 

327 

328 

329 

331 
332 
333 

334 

336 
337 
338 
339 


Protein, 
per  cent. 


12.33 

12.39 

9.64 

9.93 

10.65 

11.05 

9.89 

10  22 

11.08 

10.29 

11.72 

8.76 

11.43 
10.94 
11.18 
11.55 

13.62 

10.99 

11.07 

9.18 

11.40 
12.24 
10.06 
11.02 

10.78 
11.28 
11.09 
12.85 


Corn 
No. 


341 
342 
343 
344 

346 
347 
348 
349 

351 
352 
353 
354 

356 
357 
358 
359 

361 
362 
363 
364 

366 

367 
368 
369 

371 
372 
373 
374 


Protein, 
per  cent. 


11.65 
11.35 
10.60 
12.16 

11.63 

12.26 

8.76 

10.69 

11.39 

10.59 

9.65 

9.83 

8.63 
11.08 
11.39 

9.12 

11.63 

9.98 

10.45 

11.89 

12.01 

9.51 

11.43 

11.76 

11.75 

9.46 

11.17 

8.67 


Corn 

No. 


376 
377 
378 
379 

381 
382 
383 
384 

386 

387 

388 
389 

391 
392 
393 
394 

396 

397 
398 
399 

401 
402 

403 

404 

406 
407 
408 
409 


Protein, 
per  cent. 


10.47 

10.92 

9.32 

12.28 

9.31 
11.00 
12.23 
11.99 

12.10 
9.20 
9.76 
9.18 

12.46 
11.14 
10.03 
13.27 

9.94 
11.78 
11.30 

11.08 

11.23 
10.92 


9 
11 


72 
14 


10.44 
12.72 
12.80 
11.17 


TABLE  5. — Protein  in  Samples  of  forty-eight  Ears  of  Corn  grown  on 

Low-protein  Plot  in  1897. 


Corn 

Protein, 

Corn 

Protein, 

Corn 

Protein, 

Corn 

Protein, 

No. 

per  cent. 

No. 

percent. 

No. 

percent. 

No. 

percent. 

411 

11.37 

426 

11.46 

441 

10.25 

456 

10.16 

412 

11.47 

427 

8.29 

442 

10.28 

457 

10.22 

413 

11.36 

428 

10.19 

443 

11.40 

458 

8.22 

414 

11.15 

429 

9.69 

444 

9.34 

459 

11.92 

416 

8.88 

431 

10.98 

446 

8.84 

461 

11.61 

417 

9.26 

432 

9.67 

447 

11.27 

462 

10.85 

418 

11.62 

433 

9.91 

448 

9.05 

463 

10.04 

419 

10.43 

434 

12.85 

449 

8.95 

464 

11.68 

421 

9.60 

436 

9.38 

451 

10.80 

466 

13.98 

422 

9.93 

437 

10.03 

452 

10.07 

467 

12.55 

423 

12.45 

438 

10,97 

453 

12.13 

468 

13.89 

424 

10.43 

439 

9.28 

454 

10  04 

469 

12.19 

214 


BULLETIN    NO.     55. 


S^June, 


In  planting  the  corn  in  1898,  the  same  general  plan  of  the  previous 
year  was  followed.  Good  crops  of  corn  were  grown.  Sets  of  ten  ears 
each  were  taken  from  each  row,  duplicate  sets  being  taken  from  some 
rows,  as  will  appear  in  the  tables.  Composite  samples  to  represent 
each  row  were  made,  as  before,  by  taking  two  rows  of  kernels  from 
each  of  the  ten  ears. 

Tables  6  and  7  give  the  percentage  of  protein  in  the  seed  planted 
and  in  the  crop  produced  in  each  row  of  the  plots. 

TABLE  6.     Protein  in  Corn  Planted  and  Harvested  on  High-protein 

Plot  in  1898. 


Plot 

Corn 

planted. 

Corn  harvested. 

Plot 
row 

Corn 

planted. 

Corn  harvested. 

row 

No. 

Corn 

Protein, 

Corn 

Protein, 

No. 

Corn 

Protein, 

Corn 

Protein, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

I 
2 

384 
366 

11.99 
12.01 

820 
830 

11.18 
10.86 

13 

298 

13.58 

J960 
/  970 

11.74 
11.42 

.     3 

386 

12.10 

840 

10.64 

289 

12.99 

J980 

11.42 

4 

347 

12.26 

850 

11.26 

14 

{  990 

11. 2» 

5 

332 

12.24 

860 

11.61 

15 

276 

12.83 

1000 

11.34 

6 

306 

12.33 

870 

11.24 

16 

407 

12.72 

lOIO 

10.77 

7 

391 

12.46 

880 

11.26 

17 

307 

12.39 

1020 

11.03 

8 

281 

12.62 

890 

10.80 

18 

379 

12.28 

1030 

10.96 

9 

408 

12.80 

900 

10.55 

19 

302 

12  26 

1040 

10.47 

10 

339 

12.85 

910 

10.92 

20 

344 

12.16 

1050 

10.33 

II 

394 

13.27 

J920 
<93o 

11.06 
10.67 

21 
22 

383 
297 

12.23 
12.07 

1060 
1070 

11.58 
9.78 

12 

326 

13.62 

J940 
1  950 

11.17 
12.48 

23 
24 

304 
364 

11.97 
11.89 

1080 
1090 

10.72 
10.95 

Pl( 

Dt  aver 

iges 

12.49 



11.05 

TABLE  7.     Protein  in  Corn  Planted  and  Harvested  on  Low-protein  Plot 

in  1898. 


Plot 

Corn  planted. 

Corn  harvested. 

Plot 

row 

No. 

Corn  planted. 

Corn  harvested. 

row 

No. 

Corn 
No. 

Protein, 
per  cent. 

Corn 
No. 

Protein, 
per  cent. 

Corn 

No. 

Protein, 
per  cent. 

Corn 

No. 

Protein, 
per  cent. 

I 
2 
3 
4 
5 

6 

421 
444 
417 
449 
446 

458 

9.60 
9.34 
9.26 
8.95 
8.84 

8.22 

1 100 
mo 
1 1 20 
1130 
1 140 
j  "50 
1  1 160 

10.92     1 
11.00 
11.03 
10.06 
9.83 
10.26 
10.19 

7 

8 

9 
10 

II 
12 

427 

416 
448 
439 
436 
432 

8.29 

8.88 
9.05 
9.28 
9.38 
9.67 

j  1 170 
/  1 180 
1 190 
1200 
1210 
1220 
1230 

10.43 
11.14 
10.68 
11.16 
9.93 
10.27 
10.83 

Plot  aver: 

iges 

9.06 

10.55 

It  will  be  seen   that  the   average   protein  content  of  the  corn  from 
the  high-protein  plot  for  1898  is  11.05  ps''  cent,  while  10.55  ^s  the  aver- 


1899.] 


CHEMISTRY  OF  THE  CORN  KERNEL. 


215 


age  percentage  from  the  low-protein  plot,  making  a  difference  of  ,50 
per  cent.  The  difference  between  the  averages  becomes  .70  per  cent,  if 
we  consider  only  the  central  half  of  each  plot.  These  results  are  nearly 
the  same  as  obtained  in   1897. 

In  order  to  avoid  local  differences  in  soil  conditions,  another  plot 
of  ground  was  planted  in  1898  with  corn  of  known  protein  content. 
For  want  of  a  better  name  this  is  called  the  "Mixed-protein  Plot." 
It  contained  five  rows  of  ten  hills  each,  or  fifty  hills.  In  each  hill 
were  planted  four  kernels  of  corn  of  which  two  were  high  and  two  were 
low  in  protein  content.  The  kernels  were  so  arranged  in  the  hill  that 
the  stalk  of  corn  produced  by  each  could  be  known.  When  the  crop 
was  harvested  eight  to  ten  ears  from  both  the  high-protein  seed' and  the 
low-protein  seed  were  taken  from  each  row.  By  taking  two  rows  of 
kernels  from  each  ear  ten  composite  samples  were  made  of  which  five 
represent  the  corn  grown  in  the  five  rows  from  high-protein  seed,  and 
the  other  five  represent  the  corn  produced  in  the  same  rows  from  low- 
protein  seed. 

Table  8  shows  the  protein  content  of  the  seed  planted  and  of  the 
samples  taken  from  the  crop  harvested. 

TABLE  8.     Protein  in   Corn  Planted  and  Harvested  on  Mixed-protein  Pl^t 

IN  1898. 


Plot 

Corn  planted. 

Corn  harvested 

Corn  planted. 

Corn  harvested. 

row 
No 

Corn 

No. 

Protein, 
per  cent. 

Corn 
No. 

Protein, 
per  cent. 

Corn 
No. 

Protein, 
per  cent. 

Corn 

No. 

Protein, 
per  cent. 

I 
2 
3 
4 
5 

408 
326 
407 
304 
364 

12.80 
13.62 
12.72 
11.97 
11.89 

698 
700 
702 
704 
706 

11.24 
11.75 
12.10 
11.65 
11.81 

446 

458 
427 
416 
448 

8.84 
8.22 
8.29 
8.88 
9.05 

697 
699 
701 
703 
705 

9.72 
11.04 
10.09 
10.89 
10.58 

Plot  aver 

ages 

11.71     i 

1 

, 

10.46 

The  results  show  that  in  every  row  the  high-protein  seed  produced 
corn  with  a  higher  protein  content  than  that  produced  by  the  low-pro- 
tein seed.  The  average  protein  content  of  the  corn  from  the  high-pro- 
tein seed  is  11.  71  per  cent.,  while  10.46  is  the  average  percentage  of 
protein  in  the  corn  from  the  low-protein  seed.  This  makes  an  average 
difference  of  1.25  per  cent. 

In  order  to  obtain  more  detailed  information  from  this  plot,  twenty- 
t>vo  pairs  of  ears  were  taken  from  twenty-two  hills,  one  ear  from  each 
pair  having  grown  from  high-protein  seed  and  the  other  from  low-pro- 
tein seed.  The  protein  in  the  corn  from  each  ear  was  determined,  and 
the  results  are  given  in  Table  9. 


2l6 


BULLETIN    NO.    55. 


[June, 


TABLE  9.     Protein   in   Corn   from    forty-four   Ears  grown   on    the 

Mixed-protein  Plot  in  1898. 


From  high- 

From  low- 

From  high- 

From  low- 

Hill 

protein  seed. 

prot( 
Corn 

;in  seed. 
Protein, 

Hill 

No. 

protein  seed. 

protein  seed. 

No. 

Corn 

Protein, 

Corn 

Protein, 

Corn 

Protein, 

No.  ■ 

per  cent. 

No. 

per  cent. 

No. 

percent. 

No. 

percent. 

I 

708 

8.89 

707 

10.68 

12 

730 

12.12 

729 

9.96 

2 

710 

9.11 

709 

8.03 

13 

732 

12.20 

731 

12.06 

3 

712 

10.17 

711 

10.38 

14 

734 

8.85 

733 

9.82 

4 

714 

9.88 

713 

10.42 

15 

736 

11.55 

735 

10.23 

5 

716 

11.64 

715 

9.45 

16 

7.38 

11.56 

737 

11.19 

6 

718 

12.28 

717 

8.64 

17 

740 

11.49 

739 

8.63 

7 

720 

11.23 

719 

9.34 

18 

742 

10.04 

741 

10  49 

8 

722 

12  39 

721 

10.21 

19 

744 

9.33 

743 

7.99 

9 

724 

12.39 

723 

10.68 

20 

746 

13.55 

745 

9.14 

10 

726 

10.23 

725 

8.73 

21 

748 

11.49 

747 

14.81 

II 

728 

12.24 

727 

11.32 

22 

750 

11.73 

749 

11.16 

Av 

erages 

11.11 



10  15 

The  average  protein  content  of  the  twenty-two  ears  from  high-pro- 
tein seed  is  ii.ii  per  cent.,  while  10.15  ^s  the  average  percentage  found 
in  the  ears  grown  from  low-protein  seed,  showing  a  difference  of  .96 
])er  cent,  to  be  attributed  to  the  influence  of  the  seed  selection.  In  six  of 
the  twenty-two  pairs  the  ear  from  low-protein  seed  contains  more  protein 
than  the  ear  from  high-protein  seed,  these  six  differences  varying  from  .  2 1 
per  cent,  in  hill  3  to  3.32  per  cent,  in  hill  21.  In  sixteen  hills  the  varia- 
tion follows  the  order  of  the  seed,  the  greatest  difference  being  4,41  per 
cent,  in  hill  20.  It  should  be  stated  that  owing  to  cross  fertilization 
no  seed  corn  was  selected  from  this  plot.  Table  9  offers  some  good 
illustrations  of  the  wide  variation  in  the  chemical  composition  of 
different  ears  of  corn  grown  from  seed  of  the  same  variety,  of  the  same 
composition,  during  the  same  season,  and  in  the  same  soil.  Compare, 
for  instance,  the  corn  grown  in  hills  20  and  21.  The  corn  from  high- 
protein  seed  shows  a  difference  of  2.06  per  cent,  of  protein  in  favor  of 
hill  20,  while  the  corn  from  low-protein  seed  is  5.67  per  cent,  higher  in 
protein  in  hill  21.  Between  hills  19  and  21a  difference  of  soil  is  indicated 
by  all  results  obtained,  and  the  corn  from  the  high-protein  seed  is  only 
2.16  per  cent,  higher  in  protein  in  hill  21  than  in  hill  19,  while  a  differ- 
ence of  6.82  per  cent,  appears  in  the  corn  from  the  low-protein  seed. 

It  is  evident  that  this  apparent  individuality  of  each  particular 
corn  plant  will  admit  of  much  further  study.  The  most  probable 
explanation  which  has  occurred  to  the  writer  is,  that  the  roots  of  the 
plant  which  produces  the  corn  of  highest  protein  content  push  into  the 
surrounding  soil  somewhat  in  advance  of  the  roots  of  the  other  plants  in 


1899-]  CHEMISTRY    OF    THE    CORN    KERNEL.  217 

the  hill  and  are  thus  enabled  to  take  up  the  larger  part  of  the  available 
supply  of  nitrogen.  However,  the  marked  differences  frequently 
observed  among  different  animals  of  exactly  the  same  breeding  lead  one 
to  question  if  the  variation  in  the  supply  of  food  materials  will  entirely 
explain  this  individuality  of  the  corn  plant.  Incidentally  it  may  be 
stated  that  the  writer  has  found  different  ears  of  good  sound  Burr's 
White  corn  varying  from  7.50  to  16. 11  per  cent,  of  protein  in  the  dry 
matter.  The  fact  that  one  good  ear  of  corn  has  been  produced  with  a 
protein  content  above  16  per  cent,  is  a  promise  of  the  possibility  of 
improving  corn  in  that  direction.  This  belief  is  strengthened  by  the 
experimental  results  thus  far  obtained  at  this  Station.  A  summary  of 
these  results  will    be  found  at  the  end  of  this  bulletin. 

In  Bulletin  No.  53,  pages  138-141,  are  quoted  some  results  of 
combined  chemical  and  mechanical  study  of  the  corn  kernel.  These 
results  show  that  the  protein  in  the  corn  kernel  is  contamed  principally 
in  the  glutenous  layer  surrounding  the  main  body  of  the  kernel.  This 
layer  is  very  thin  at  the  crown  of  the  kernel,  but  quite  thick  at  the  sides. 
The  germ,  in  the  center  of  the  tip  end  of  the  kernel  is  also  rich  in  pro- 
tein, although  the  entire  germ  constitutes  only  about  12  per  cent,  of  the 
kernel.  The  starchy  portion,  lying  between  the  germ  and  the  glutenous 
layer  and  occupying  also  the  center  of  the  crown  end  of  the  kernel, 
consists  almost  entirely  of  carbohydrates,  although  the  glutenous  layer 
contains  also  a  large  percentage  of  carbohydrates. 

On  the  basis  of  this  knowledge  of  the  general  structure  of  the  corn 
kernel  and  chemical  composition  of  its  several  parts,  the  writer  has 
made  some  investigations  as  to  the  possibility  of  selecting  corn  of  high 
protein  content  and  of  low  protein  content  by  purely  mechanical  means, 
and  has  found  that  such  a  method  is  both  possible  and  practicable. 

By  making  cross  sections  and  longitudinal  sections  of  several  ker- 
nels from  an  ear  of  corn,  one  can  judge  with  a  very  satisfactory  degree 
of  accuracy  whether  the  corn  is  rich  or  poor  in  protein.  The  illustra- 
tion (Fig.  i)  here  shown  was  made  from  a  photograph  taken  of  the  corn 
kernels  and  sections  with  a  magnification  of  three  diameters.  At  the 
left  are  two  sections  and  a  whole  kernel  from  corn  No.  945,  containing 
14.92  per  cent,  of  protein.  The  sections  and  whole  kernel  at  the  right 
are  from  corn  No.  1104,  containing  7.76  per  cent,  of  protein.  About 
one-fourth  of  the  kernel  was  cut  off  from  the  tip  end  in  making  the 
cross  sections.  In  the  longitudinal  sections  the  tip  end  of  the  kernel 
points  upward  to  the  right.  It  will  be  seen  that  in  the  cross  sections 
the  white,  starchy  layer  nearly  disappears  in  the  high-protein  corn  but 
becomes  very  prominent  in  the  low-protein  corn.  In  the  longitudinal 
sections  this  difference  is  also  apparent,   the  white  starch   in  the  high- 


2l8 


Corn  No 

Protein,  per  cent. 


BULLETIN    NO.    55.    ' 

945    1 104 

14.92 7.76 


{June, 


Figure  i. 

protein  corn  being  confined  almost  entirely  to  the  crown  end  of  the 
kernel,  while  in  the  low-protein  corn  it  extends  into  the  tip  end  in  con- 
siderable amount.  The  germ  in  the  high-protein  corn  is  somewhat 
larger.      This  is  also  indicated  by  the  depressions  in  the  whole  kernels. 

As  an  experiment  a  number  of  ears  of  both  high  and  low  content 
of  protein  were  mixed  together  and  then  separated  by  mechanical  exam- 
ination. It  was  found  that  by  examining  only  one  or  two  kernels  from 
each  ear  the  separation  could  be  made  with  very  few  errors. 

In  order  to  make  a  more  practical  test  three  hundred  eighteen  ears 
of  corn  were  examined.  The  protein  content  of  the  ears  in  the  entire 
lot  did  not  vary  as  much  as  would  ordinarily  be  the  case,  because 
thirty-four  of  the  ears  highest  in  protein  and  twenty  six  of  those  lowest 
in  protein  had  already  been  removed  from  this  lot  of  corn.      From  what 


1899] 


CHEMISTRY    OF    THE    CORN    KERNEL. 


219 


remained,  however,  eighteen  ears  were  picked  out  by  mechanical  exam- 
ination as  possessing  the  physical  characteristics  which  indicate  a  com- 
paratively high  content  of  protein,  fifteen  ears  which  appeared  to  be 
low  in  protein  being  selected  at  the  same  time.  Table  10  shows  the 
results  in  detail,  the  percentage  of  protein  in  the  corn  from  each  ear 
being  given  as  previously  determined  by  chemical  analysis. 


TABLE  10.     Actual  Protein  Content  of  Corn  Selected  by  Mechanical 

Examination. 


Corn  selected  for 

Ear 

No. 

7 
8 

9 
10 
II 
12 

Corn  selected  for 

Ear 

No. 

Corn  selected  for 

Ear 

No. 

High 
protein. 

Low 
protein. 

High 
protein. 

Low 
protein    | 

High 
protein. 

Low 
protein 

Percent. 

Percent. 

Percent 

Percent. 

Percent. 

Percent. 

I 
2 
3 
4 
5 
6 

11.47 
12.04 
9.69 
11.78 
11.65 
11.38 

11.48 
9.06 
9.90 
9.15 
9.67 

10.11 

11.64 
11.22 
11.97 
11.94 
10.96 
10.83 

9.11 
10.25 
8.63 
9.63 
8.61 
10.95 

13 
14 
15 
16 

17 
18 

11.87 
10.21 
11.71 
11.59 
12.31 
10.54 

11.27 

9.36 

10.25 

Av 

erages .... 

11.38 

9  83 

The  average  protein  content  of  the  eighteen  ears  selected  for  high- 
protein  corn  is  11.38  per  cent.,  while  9.83  is  the  average  percentage  of 
protein  in  the  fifteen  ears  selected  for  low-protein  corn.  Only  one  ear 
(No.  3)  selected  for  high-protein  corn  contains  less  than  9.83  per  cent., 
and  a  single  ear  (No.  i)  also  selected  for  low  protein  corn  contains 
more  than  11.38  per  cent. 

Table  11  shows  the  results  obtained  in  picking  out  corn  by  mechan- 
ical examination  from  a  lot  which  contained  corn  of  only  very  high  or 
very  low  protein  content. 

TABLE  II.      Actual   Protein    Content   of   Corn    Separated   by 
Mechanical  Examination. 


Corn  selected  for 

Ear 

No. 

Corn  selected  for 

Ear 

No. 

Corn  selected  for 

Ear 

No. 

High 
protein. 

Low 
protein. 

High 
protein 

Low 
protein. 

High 
protein. 

Low 
protein. 

Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

I 
2 
3 
4 
5 

13.03 
12.88 
14.92 
14.05 
12.97 

13.46 

8.82 

13.05 

8.95 

7.76 

6 

7 
8 

9 
10 

12.83 
13.25 
12.98 
13.04 
12.82 

12.39 
8.57 
9.02 
7.85 
8.29 

II 
12 
13 
14 
15 

12.78 
12.97 
13.04 
16.08 
12.30 

8.32 
7.85 
8.58 
7.50 
8.62 

2  20  BULLETIN    NO.    55.  \^June, 

It  will  be  seen  that  no  errors  were  made  in  selecting  corn  of  high 
protein  content,  while  three  mistakes  occurred  in  picking  out  low-pro- 
tein corn.  It  maybe  stated,  however,  that  these  separations  were  com- 
monly made  upon  the  examination  of  but  one  kernel  from  each  ear, 
and  in  no  case  were  more  than  two  kernels  from  an  ear  examined. 

The  examination  consists  in  simply  cutting  cross  sections  and  lon- 
gitudinal sections  from  the  kernels  with  a  pocket  knife  and  judging  as  to 
the  combined  amount  of  glutenous  layer  and  germ  in  relation  to  the 
quantity  of  the  white  starchy  matter,  the  observation  being  made  with 
the  naked  eye.  Some  difificulties  are  met  in  attempting  to  form  a  cor- 
rect opinion  as  to  whether  a  kernel  is  rich  or  poor  in  protein.  For 
instance,  the  disposition  of  the  white  starchy  matter  is  not  strictly  uni- 
form in  all  kernels.  It  sometimes  happens  that  the  tip  end  of  the  kernel 
contains  but  very  little  white  starch  and  a  cross  section  near  that  end 
would  indicate  a  high  protein  content,  but  at  the  crown  end  there  may 
be  an  excessive  proportion  of  starch  and  the  kernel  as  a  whole  be  low 
in  protein.  For  this  reason  it  is  important  that  both  cross  sections  and 
longitudinal  sections  be  made  before  judgment  is  taken.  Another  diffi- 
culty is  caused  by  the  great  variation  in  the  size  of  kernels  of  corn  from 
different  ears.  A  very  large  kernel,  for  example,  may  show  a  consider- 
able quantity  of  white  starch,  extending  even  to  the  tip  of  the  kernel, 
and  yet  contain  a  high  percentage  of  protein. 

In  making  the  selections  given  in  Tables  lo  and  ii,  the  time  given 
to  each  ear  was  about  a  half  minute,  and  it  is  not  assumed  that 
the  writer  possesses  any  special  skill  in  judging  the  comparative  sizes  of 
small  areas  or  surfaces,  the  chief  point  involved  in  making  these  ex- 
aminations. Indeed,  it  seems  but  fair  to  suppose  that  the  average  corn 
grower  could,  with  some  practice  and  care,  make  a  better  selection. 
In  fact,  the  selections  here  shown  were  made  upon  material  which  was 
at  hand  and  for  the  purpose  of  showing  the  feasibility  of  the  method, 
rather  than  the  extent  to  which  it  may  be  carried. 

The  question  whether  the  size  of  the  corn  kernel  bears  any  special 
relation  to  the  percentage  of  protein  it  contains  was  investigated. 
Tables  12  and  13  give  the  average  weights  in  grams  of  the  air-dry 
kernels  from  forty  different  ears  which  were  used  in  1899  as  seed  for  the 
high-protein  and  low-protein  plots.  The  percentage  of  protein  in  the 
dry  matter  is  also  shown. 


1899-] 


CHEMISTRY    OK    THE    CORN    KERNEL. 


22  I 


TABLE  12.     Average  Weights  of  Kernels  from  twenty-four  Ears  of 

High-protein  Corn. 


Ear 

Corn 

Kernel, 

Protein, 

Ear 

Corn 

Kernel, 

Protein. 

No. 

No. 

ave.  wt. 

per  cent. 

No. 

No. 

ave   wt. 

per  cent. 

I 

1045 

.470 

12.35 

13 

951 

.410 

14.25 

2 

1039 

.290 

12.39 

14 

895 

.330 

13.46 

3 

851 

.355 

12.48 

15 

962 

.400 

13.25 

4 

1096 

.370 

12.74 

16 

984 

.430 

13.12 

5 

826 

.390 

12.83 

17 

864 

.310 

13.04 

.       6 

961 

.340 

12.97 

18 

lOII 

.405 

12.99 

7 

1062 

.395 

13-03 

19 

976 

.320 

12.98 

8 

845 

.440 

13.05 

20 

1004 

.420 

12  88 

9 

953 

.355 

13.21 

21 

871 

.375 

12.82 

ID 

985 

.375 

13.34 

22 

904 

.405 

12.55 

11 

959 

.360 

14.05 

23 

885 

.325 

12.45 

12 

945 

.370 

14.92 

24 

1055 

.295 

12.37 

Gener 

al  average 

.372 

TABLE  13.     Average   Weights   of   Kernels   from    sixteen    Ears   of 

Low-protein  Corn. 


Ear  No. 

Corn 

Kernel. 

Protein, 

Ear  No. 

Corn 

Kernel, 

Protein, 

No. 

ave.  wt. 

per  cent. 

No. 

ave.  wt. 

per  cent. 

I 

1159 

.385 

9.02 

y 

1 104 

.410 

7.76 

2 

1188 

.355 

8.83 

10 

1165 

.355 

7.85 

3 

1211 

.305 

8.66 

II 

1225 

.280 

8.32 

4 

1149 

.290 

8.62 

12 

1131 

.310 

8.58 

5 

1139 

.345 

8.57 

13 

1173 

.335 

8.63 

6 

1167 

.340 

8.29 

14 

1219 

.360 

8.82 

7 

"33 

.360 

7.85 

15 

1151 

.350 

8.90 

8 

1144 

.275 

7.50 

16 

1184 

.335 

8.95 

Genei 

al  average 

.337 

The  weight  of  kernels  is  shown  to  vary  from  .290  to  .470  gram  in 
the  high-protein  corn,  and  from  .275  to  .410  gram  in  the  low-protein 
corn,  with  a  difference  between  the  general  averages  of  .035  gram.  It 
is  evident  that  the  actual  weight  of  the  kernel  gives  very  little,  if  any, 
indication  as  to  the  percentage  of  protein  which  it  contains.  This  is 
illustrated  in  Figures  2  and  3. 


222 


BULLETIN    NO.    55. 


l/une. 


Corn  No 

Protein,   per  cent. 
Kernel,  ave.  wt.  . 


945   •  ••    1 104 

14.92 7.76 

.370 410 


Figure  2. 
Figure  2  shows   high-protein   corn,  No.  945,  containing    14.92   per 
cent,  of  protein,  at  the  left,  and  at  the  right  low-protein  corn,  No.  1104, 
with  larger  kernels  but  containing  little  more  than  half  as  much  protein, 
7.76  per  cent. 


1899-]  CHEMISTRY    OF    THE    CORN    KERNEL. 

Corn  No 951    1 1 49 

Protein,   per  cent   14. 25     8.62 

Kernel,  a ve  wt.  .         .410 290 


223 


Figure  3. 

P'igure  3  shows  corn  containing  14.25  per  cent,  of  protein,  No. 
951,  at  the  left,  and  at  the  right  No.  1149,  with  smaller  kernels  contain- 
ing 8.62  per  cent,  of  protein. 


224 


BULLETIN    NO.    55. 


[A««?, 


EXPERIMENTS  TO  INFLUENCE  THE  FAT 
CONTENT  OF  CORN. 

From  the  lot  of  one  hundred  sixty-three  ears  of  corn  from  the  1896 
crop,  the  analyses  of  which  are  given  in  Table  i,  seed  was  selected  for 
the  high-fat  and  low-fat  plots  for  1897,  as  already  explained  (see  page 
210).  Tables  14  and  15  show  the  percentage  of  fat  in  the  seed  planted 
and  in  the  crop  produced. 

TABLE  14.     Fat  in  Corn  Planted  and  Harvested  on  High-fat  Plot 

IN  1897. 


Plot 

Corn 

planted. 

Corn  harvested. 

Plot 
row 

No. 

Corn 

planted. 

Corn  harvested. 

row 
No. 

Corn 

Fat, 

Corn 

Fat,   1 

Corn 

Fat. 

Corn 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

1 

118 

5.02 

13 

171 

5.75 

520 

4.99 

2 

163 

5.09 

14 

162 

5.61 

525 

4.84 

3 

136 

5.10 

470 

4.43 

15 

98 

5.51 

530 

5.23 

4 

220 

5.23 

475 

4.74 

ir, 

205 

5.36 

535 

4.70 

5 

201 

5.22 

480 

4.77   1 

17 

122 

5.25 

540 

4.47 

6 

174 

5.22 

485 

4.65   1 

18 

139 

5.23 

545 

4.81 

7 

77 

5.24 

490 

4.50 

19 

235 

5.27 

550 

4.38 

8 

i«3 

5.46 

495 

4.53 

20 

106 

5.21 

555 

4.80 

C 

95 

5.51 

500 

4.98 

21 

2.38 

5.20 

560 

4.58 

lO 

189 

5.63 

505 

4.75 

22 

237 

5.13 

565 

4.46 

II 

109 

5.65 

510 

5.40   ! 

23 

154 

5.02 

12 

236 

6.02 

515 

4.65 

24 

144 

4.99 

PI 

Dt  aver? 

iges 

5.33 

4  73 

TABLE  15.     Fat  in  Corn  Planted  and   Harvested  on  Low-fat  Plot  in   1897. 


Corn 

planted. 

Corn 

larvested. 

, 

Corn 

larvested. 

Corn 

planted. 

Plot 

Plot 

row 
No. 

Corn 

Fat, 

Corn 

Fat, 

row 
No. 

Corn 

Fat, 

Corn 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

1 

149 

4.08 

7 

182 

3.94 

595 

4.01 

I 

152 

4.09 

570 

3.96 

8 

123 

4.01 

600 

4.06 

3 

150 

4.03 

575 

4.21 

9 

228 

4.12 

605 

3.97 

4 

192 

4.07 

580 

4.31 

lO 

133 

4.10 

610 

4.05 

5 

196 

3.95 

585 

4.05 

II 

212 

4.12 

615 

4.22 

6 

166 

3.84 

590 

3.79 

12 

156 

4.14 

Plot  aver; 

iges 

4.04 

4.06 

These  results  indicate  that  the  fat  content  of  corn  is  influenced 
very  markedly  by  selecting  seed  according  to  its  percentage  of  fat. 
The  average  fat  content  of  the  seed  for  the  high-fat  plot  is  5.33  per 
cent.,  while  4.04  is  the  average  percentage  in  the  seed  for  the  low-fat 
plot.      This  shows  an  average  difference  in  the  seed  for  the  two  plots   of 


1899.] 


CHEMISTRY    OF    THE    CORN    KERNEL. 


225 


1.29  per  cent,  of  fat.  The  difference  between  the  average  fat  contents 
of  the  crops  from  the  two  plots  is  .67  per  cent.,  the  average  from  the 
high-fat  plot  being  4.73  and  from  the  low-fat  plot  4.06  per  cent,  of  fat. 
There  is  a  difference  of .  79  per  cent,  of  fat  between  the  averages  of  the  two 
crops,  if  we  consider  only  the  central  half  of  each  plot.  It  is  noteworthy 
that  the  lowest  percentage  of  fat  in  the  corn  from  any  row  of  the  high- 
fat  plot,  namely,  4.38  per  cent,  in  row  19,  is  higher  than  the  highest 
percentage  obtained  from  any  row  in  the  low-fat  plot. 

It  will  be  seen  that  samples  were  not  taken  from  some  of  the  outer 
rows  in  these  plots,  namely,  rows  i,  2,  23,  and  24  in  the  high-fat  plot, 
and  rows  i  and  12  in  the  low-fat  plot.  From  all  other  rows  sets  of  ten 
ears  each  were  taken,  the  results  here  given  being  obtained  by  the 
analysis  of  the  composite  sample  for  each  row. 

From  each  set  of  ten  ears  from  the  1897  crop,  four  ears  were  taken 
for  individual  analysis,  a  sample  of  three  or  four  rows  of  kernels 
(lengthwise  of  the  ear)  being  taken  for  this  purpose.  In  these  samples 
only  fat  and  dry  matter  were  determined.  The  system  of  numbering 
the  samples  was  the  same  as  that  followed  in  the  experiments  with  the 
protein  content  of  corn,  the  multiple  of  five  being  given  to  the  compo- 
site sample  and  the  next  four  numbers  to  the  samples  of  four  single  ears 
from  the  same  row.  Thus,  the  composite  sample  from  row  3,  high-fat 
plot,  1897,  is  numbered  470  (Table  14),  and  the  four  samples  of  indi- 
vidual ears  from  the  same  row  are  numbered  471,  472,  473,  and  474 
(Table   16). 

TABLE  16.      Fat    in    Samples   of   eighty   Ears   of   Corn   grown    on    High-fat 

Plot  in  1897. 


Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

1 
Corn 

Fat, 

No. 

percent. 

No. 

percent. 

No. 

percent. 

No. 

percent. 

No. 

per  cent. 

471 

4  44 

491 

4  85 

511 

5  44 

531 

5  04 

551 

431 

472 

4.79 

492 

4  38 

1     512 

5.45 

532 

4  82 

552 

4  33 

473 

4  42 

493 

4  93 

1     .S13 

5  49 

.533 

4  98 

553 

4  24 

474 

4  59 

494 

4  97 

514 

5  39 

534 

5  27 

554 

4  33 

476 

484 

496 

4.26 

S16 

4  63 

536 

4  97 

556 

4  93 

477 

4  82 

497 

4  59 

517 

5  26 

537 

4  50 

557 

4  68 

478 

5  39 

498 

4  76 

S18 

4  81 

538 

4  92 

558 

4  92 

479 

4  40 

499 

4.45 

519 

4  44 

539 

4.83 

559 

5  12 

481 

504 

SOI 

5  45 

52  X 

4.98 

541 

4  78 

561 

441 

482 

4  87 

502 

4  95 

522 

4  22 

542 

3  60 

562 

4  62 

483 

4.46 

503 

4  64 

523 

4  91 

543 

4  91 

563 

4  95 

484 

507 

504 

4  77 

524 

5.68 

544 

502 

564 

4  23 

486 

5  03 

506 

491 

526 

4.70 

546 

5  20 

566 

4.39 

487 

420 

S07 

4  69 

527 

5  43 

547 

500 

567 

4.20 

488 

4.72 

508 

5  04 

528 

5  12 

54S 

4  90 

568 

5  05 

489 

4  86 

509 

420 

529 

4.68 

549 

481 

569 

4  42 

226 


BULLETIN    NO.     55. 


I  June, 


TABLE  17.     Fat  in  Samples  of  forty  Ears  of  Corn  grown  on  Low-fat  Plot 

IN     1897. 


Corn' 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No, 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

571 

4.00 

.581 

4  74 

591 

3.85 

601 

4  68 

611 

3  84 

572 

3.96 

.582 

4  69 

592 

3.72 

602 

3  55 

612 

408 

573 

3.89 

.583 

4  65 

593 

3  38 

603 

3  8<> 

613 

4  39 

574 

383 

584 

407 

594 

3.39 

604 

4  42 

614 

3  39 

576 

4.21 

586 

4  21 

596 

4  21 

606 

3  50 

1  616 

4  08 

577 

4  28 

587 

4  74 

597 

4  22 

607 

4  40 

617 

4  19 

578 

4.18 

588 

370 

598 

4  42 

608 

3  90 

618 

4  43 

579 

4  41 

589 

3  85 

599 

4.04 

609 

3  90 

619 

4  68 

Eighty  samples  of  single  ears  from  the  high-fat  plot  and  forty  from 
the  low-fat  plot  were  analyzed.  The  percentage  of  fat  in  the  dry  matter 
is  given  in  Tables  i6  and  17. 

It  will  be  remembered  that  extreme  variations  are  common  in  the 
protein  content  of  different  ears  of  corn  even  when  grown  the  same  sea- 
son, from  seed  of  uniform  protein  content,  and  in  practically  the  same 
soil.  Such  variations  do  not  seem  characteristic  of  the  fat  content.  Of 
the  eighty  ears  selected  from  the  high-fat  plot,  only  one  contained  less 
than  4.20  per  cent,  of  fat,  while  4.06  is  the  average  percentage  of  fat 
in  the  corn  from  the  low-fat  plot.  On  the  other  hand  no  ear  from  the 
low-fat  plot  was  found  to  contain  above  4.74  per  cent,  of  fat,  although 
60  per  cent,  of  the  ears  from  the  high-fat  plot  contained  above  that  per- 
centage of  fat,  the  maximum  being  5.68  per  cent. 

For  1898  the  seed  for  the  high-fat  plot  was  from  corn  which  grew 
on  the  high-fat  plot  in  1897,  twenty-four  of  the  eighty  ears  whose  fat 
content  is  shown  in  Table  16  being  selected.  For  the  low-fat  seed 
twelve  ears  were  selected  from  the  forty  ears  whose  percentage  of  fat  is 
shown  in  Table  17,  all  of  which  were  grown  from  low-fat  seed  in  1897. 
The  system  of  planting  the  highest  of  the  high-fat  seed  and  the  lowest 
of  the  low-fat  seed  in  the  middle  rows  of  the  respective  plots  was  fol- 
lowed in  1898.  Good  crops  of  corn  were  grown,  and,  when  harvested, 
sets  of  ten  ears  each  were  taken  from  each  row,  composite  samples  to 
represent  each  row  being  made,  as  before,  by  taking  two  rows  of  kernels 
from  each  of  the  ten  ears. 

Tables  18  and  19  give  the  percentage  of  fat  in  the  composite 
samples  and  also  in  the  seed  planted  in  each  row. 


l899-]  CHEMISTRY    OF    THE    CORN    KERNEL.  227 

TABLE  i8.     Fat  in  Corn  Planted  and  Harvested  on  High-fat  Plot  in  1898. 


Corn 

planted. 

Comb 

larvested. 

• 

Corn 

planted. 

Corn  harvested. 

Plot 

Plot 
rowv 

row 

No. 

Corn 

Fat. 

Corn 

Fat, 

No. 

Corn 

Fat, 

Corn 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

I 

521 

4  98 

1240 

4.86 

13 

513 

5  49 

1360 

5  21 

2 

533 

4  98 

1250 

4  74 

14 

512 

545 

1370 

5  44 

3 

486 

5  03 

1260 

4  94 

15 

527 

5  43 

1380 

5  48 

4 

531 

5  04 

1270 

5  17 

16 

514 

5  39 

1390 

5  26 

5 

568 

5  05 

1280 

5  36 

17 

517 

5  26 

1400 

5  55 

6 

528 

5  12 

1290 

4  79 

18 

559 

5  12 

1410 

5  23 

7 

546 

5  20 

1300 

4  87 

19 

484 

5  07 

1420 

5  06 

8 

534 

5  27 

1310 

5  20 

20 

544 

502 

1430 

4  89 

9 

478 

5  39 

1320 

5  16 

21 

508 

5  04 

1440 

5  00 

10 

5" 

5  44 

1330 

5  25 

22 

547 

5.00 

1450 

5  10 

II 

501 

5.45 

1340 

5  21 

23 

5,36 

4  97 

1460 

5  05 

12 

524 

5  68 

1350 

563 

24 

494 

4  97 

1470 

5  21 

Pl< 

3t  averj 

iges 

5  20 

5  15 

TABLE  19.     Fat  in  Corn  Planted   and    Harvested  on   Low-fat  Plot 

in  1898. 


Plot 

Corn  planted. 

Corn  harvested. 

Plot 
row 

No. 

Corn 

planted. 

Corn  harvested. 

row 

No. 

Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

Corn 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

percent 

I 

589 

3.85 

1480 

3.97 

7 

593 

3.38 

1540 

3.69 

2 

574 

3.83 

1490 

4.32 

8 

606 

3.50 

1550 

3.78 

3 

592 

3.72 

1500 

4.08 

9 

588 

3.70 

1560 

3  93 

4 

602 

3.55 

1510 

3.99 

10 

603 

3.80 

1570 

4.18 

5 

594 

3.39 

1520 

3.81 

II 

611 

3.84 

1580 

4.21 

6 

614 

3.39 

1530 

3.81 

12 

591 

3.85 

1590 

4.11 

PI 

Dt  aven 

iges 

3.65 

3  99 

The  average  fat  content  of  the  corn  from  the  high-fat  plot  for  1898 
is  5.15  per  cent.,  while  3.99  is  the  average  percentage  of  fat  in  the 
corn  from  the  low-fat  plot,  making  a  difference  of  1.16  per  cent,  between 
the  averages,  and  the  difference  becomes  1.45  per  cent,  if  we  consider 
only  the  central  half  of  each  plot,  or  1.56  per  cent,  if  only  the  central 
third  of  each  plot  is  considered.  The  effect  of  planting  the  seed  in 
gradation  as  to  fat  content  from  the  center  rows  to  either  side  is  decid- 
edly noticeable  in  the  crop.  It  is  only  necessary  to  take  averages  of 
the  fat  content  of  the  composite  samples  from  the  high-fat  plot  in 
groups  of  four  to  obtain  a  regular  gradation  in  the  same  order  as  tha 
of  the  seed.     Thus, — 


2  28  BULLETIN    NO.    55.  [^JunCy 

Corn  Fat, 

from  rows.  average  per  cent. 

1-  4 4.93 

5-  8 5.06 

9-12   ,5.31 

13-16 5.35 

17-20 5.18 

21-24   5.09 

In  the  low-fat  plot  the  percentages  of  fat  in  the  composite  samples 
from  the  single  rows  are  in  regular  gradation,  if  we  omit  only  the  out- 
side rows,  Nos.  I  and  12.     This  maybe  seen  in  Table  19. 

There  is  some  indication  of  the  influence  of  the  season  upon  the 
fat  content  of  corn,  which  becomes  apparent  by  comparing  the  results 
obtained  in  the  two  different  years  1897  and  1898  (see  Table  20). 

TABLE  20.     Average  Percentages  of  Fat   in   Corn   Planted   and    Harvested 

IN    1897    AND    1898 


Season    

1897. 

i8q8. 

Fat  in  corn  planted 

■5.^^           ';-2o 

Fat  in  corn  harvested 

4-73 

5-15 

High-fat  plot. 

Difference 

.60 

.05 

Fat  in  corn  planted 

4.04 
4.06 

3.6"; 

Low-fat  plot. 

Fat  in  corn  harvested 

3.99 

Difference 

.02 

.34 

The  season  of  1897  seems  to  have  favored  the  production  of  corn 
of  low  fat  content,  the  average  percentage  of  fat  in  the  crop  from  the 
low-fat  plot  being  but  .02  per  cent,  higher  than  in  the  seed,  while  in  the 
high-fat  plot  the  crop  is  .60  per  cent,  below  the  seed  in  fat  content. 
In  1898  the  production  of  corn  high  in  fat  seems  to  have  been  favored, 
the  fat  content  of  the  crop  being  only  .05  per  cent,  below  that  of  the 
seed  in  the  high-fat  plot  and  .34  above  that  of  the  seed  in  the  low- 
fat  plot. 

In  1898  a  third  plot  of  ground  for  the  study  of  the  fat  content  of  corn 
was  planted.  This  is  called  the  "Mixed-fat  Plot,"  and  was  planted 
after  the  same  plan  as  the  mixed-protein  plot.  It  contained  fifty  hills 
arranged  in  five  rows  of  ten  hills  each.  In  each  hill  two  kernels  of 
high-fat  corn  were  planted  on  one  side  and  two  of  low  fat  content  on  the 
other.  The  special  object  in  this  work  was,  of  course,  to  avoid  the 
influence  of  soil  differences.     When  the  crop  was  harvested   composite 


1899] 


CHEMISTRY  OF  THE  CORN  KERNEL. 


229 


samples  were  made  of  the  corn  from  each  side  of  each  row,  two  rows  of 
kernels  from  eight  to  ten  ears  being  used  for  each  composite  sample. 
Table  21  shows  the  fat  content  of  the  seed  and  of  the  crop  for  each  side 
of  each  row. 
TABLE  21.     Fat  in  Corn  Planted  and  Harvested  on  Mixed-fat  Plot  in  1898. 


Plot 
row 

No. 

Corn  planted. 

Corn  harvested. 

Corn  planted. 

Corn  harvested. 

Corn 

No. 

Fat. 
percent. 

Corn 
No. 

Fat, 
percent 

Corn 
No. 

Fat, 
per  cent. 

Corn 

No. 

Fat, 
percent. 

I 
2 
3 
4 

5 

546 
511 
524 
513 
527 

5  20 
5  44 
5  68 
5  49 
5  43 

752 
754 
756 
758 
760 

4  66 

4  87 

5  38 
5.14 
535 

594 
614 

593 
606 

588 

3  39 
3  39 
3  38 
3  50 
3  70 

751 
753 
755 
757 
759 

3.60 

3  86 

4  13 
4  20 
4  06 

Plnf    aupr 

A0PS 

5  08 

3  97 

The  difference  between  the  average  fat  content  of  the  corn  from 
high-fat  seed  and  that  from  low-fat  seed  is  i.ii  per  cent.  ■  The  lowest 
fat  content  of  any  composite  sample  from  high-fat  seed  is  4.66  per 
cent.,  and  4.20  is  the  highest  percentage  of  fat  in  a  composite  sample 
of  corn  from  low-fat  seed. 

From  the  mixed-fat  plot  twenty-seven  pairs  of  ears  were  taken 
from  twenty-seven  hills,  one  ear  in  each  pair  having  grown  from  high- 
fat  seed  and  the  other  ear  from  low-fat  seed.  Table  22  gives  the  fat 
content  in  the  corn  from  each  of  these  ears. 

TABLE  22.     Fat  in  Corn  from  fifty-four  Ears  grown  on  the  mixed-fat 

Plot  in  1898. 


From 

hish-fat 

From 

low-fat 

From 

high-fat 

From 

low-fat 

seed. 

seed. 

seed 

seed. 

Hill 

Hill 

No. 

Corn 

Fat. 

Corn 

Fat, 

No. 

Corn 

Fat, 

Corn 

Fat. 

No. 

per  cent. 

No 

per  cent. 

No. 

per  cent 

No. 

per  cent. 

I 

762 

4.05 

761 

3.82 

14 

78S 

5.03 

787 

4.08 

2 

764 

4.42 

763 

3.62 

15 

790 

5.57 

789 

3.57 

3 

766 

4.65 

765 

3.03 

16 

792 

5.32 

791 

4.69 

4 

768 

4  90 

767 

3.92 

17 

794 

5.75 

793 

3.96 

5 

770 

5.16 

769 

3.94 

18 

796 

4.95 

795 

4.64 

6 

772 

5.06 

771 

3.99 

19 

798 

4.79 

797 

4.30 

7 

774 

5.13 

773 

4.15 

20 

800 

4  59 

799 

4  33 

8 

776 

4.95 

775 

3.75 

21 

802 

5.56 

801 

3.77 

9 

778 

5.59 

777 

3.60 

22 

804 

5.34 

803 

4.17 

10 

780 

4.10 

779 

4.04 

23 

806 

4.92 

S05 

4.50 

II 

782 

4.49 

781 

3.56 

24 

808 

5.91 

807 

3.58 

12 

784 

5.25 

783 

4.26 

25 

810 

5.86 

809 

4.55 

13 

786 

5.65 

785 

4.15 

26 

812 

4.59 

811 

3.96 

27 

814 

5.02 

813 

4.23 

A\ 

.ferages 



5.06 

4.01 

230  BULLETIN    NO.     55.  \^/une, 

The  average  percentage  of  fat  in  the  twenty-seven  ears  from  high- 
fat  seed  is  5.06,  while  4.01  per  cent,  is  the  average  fat  content  of  the 
same  number  of  ears  from  low-fat  seed.  It  is  interesting  to  note  that 
in  the  twenty-seven  hills  there  is  no  instance  where  the  ear  of  corn  from 
high-fat  seed  does  not  contain  more  fat  than  the  ear  grown  from  low-fat 
seed  in  the  same  hill.  The  difference  in  fat  content  between  ears  in  the 
same  hill  varies  from  .06  per  cent,  in  hill  No.  10  to  2.33  per  cent,  in 
hill  No.  24. 

The  ear  which  grew  from  low-fat  seed  in  hill  No.  3  has  the  lowest  fat 
content,  3.03  per  cent.,  of  any  ear  of  corn  which  has  been  analyzed  in 
these  experiments.  The  maximum  fat  content  which  has  been  found  in 
an  ear  of  Burr's  White  corn  up  to  the  present  time  is  6.71  per  cent.  It 
seems  reasonable  to  suppose  that  these  limits  may  be  reached  again  or 
exceeded,  and  possibly  by  corn  in  larger  amounts  than  single  ears.  The 
experiments  upon  the  fat  content  of  corn  are  summarized  at  the  end  of 
this  bulletin. 

The  fact  that  the  fat,  or  oil,  of  the  corn  kernel  is  contained  almost 
entirely  in  the  germ  (see  Bulletin  No.  53,  pages  139  and  140)  suggested 
to  the  writer  the  possibility  of  selecting  corn,  of  high  or  low  fat  con- 
tent by  mechanical  examination  of  the  kernel  and  judging  as  to  the  quan- 
tity of  germ  compared  with  the  remainder  of  the  kernel.  It  was  found  that 
the  method  is  possible  and  rather  more  satisfactory  than  the  method 
(already  described)  of  judging  the  protein  content  of  the  corn  kernel  by 
mechanical  examination,  as  it  is  less  complicated  than  the  latter. 

Figure  4  (made  from  a  photograph  taken  with  a  magnification  of 
three  diameters)  illustrates  the  difference  in  corn  kernels  of  about  the 
same  size  but  of  very  different  fat  content.  The  cross  sections,  shown 
at  the  top,  were  made  by  cutting  off  about  one-fifth  of  the  kernel  from 
the  tip  end.  In  the  longitudinal  sections  the  tip  end  of  the  kernel 
points  downward  to  the  left.  The  sections  and  kernel  shown  at  the 
left  are  from  an  ear  of  corn  (No.  1338)  which  contains  6.0S  per  cent, 
of  fat.  Those  at  the  right  are  from  an  ear  (No.  15  12)  containing  3.64 
per  cent,  of  fat. 

It  will  be  seen  that  the  germ  is  larger  in  the  high-fat  corn  and  that 
it  extends  nearly  the  entire  length  of  the  kernel,  while  in  the  low-fat 
corn  the  germ  is  small  and  about  two-thirds  as  long  as  the  kernel. 
Aside  from  the  rather  slight  difference  in  the  size  of  the  depressions, 
the  general  appearance  of  the  whole  kernels  is  about  the  same  whether 
they  are  rich  or  poor  in  fat  content.  This  is  true  also  of  ears  with 
kernels  of  about  the  same  size,  as  may  be  seen  from  Figure  5  which 
illustrates  the  two  ears  from  which  were  taken  the  kernels  shown  in 
Figure  4,  the  high-fat  ear  being  at  the  left  and    the  low-fat  at  the  right. 


1899-] 


CHEMISTRY  OF  THE  CORN  KERNEL 


231 


Corn  No 1338 1512 

Fat,  percent 6.08 3.64 


Figure  4. 

There  is  apparently  some  tendency  toward  large  kernels  with  ears 
of  corn  having  a  low  fat  content,  and  vice  versa,  indicating  that  the 
change  in  the  percentage  of  fat  is  brought  about,  in  part,  at  least,  by 
the  absolute  increase  or  decrease  of  carbohydrates.  In  other  words, 
in  selecting  seed  with  a  low  percentage  of  fat,  as  determined  by  chem- 
ical analysis,  the  ears  chosen  will  have  a  tendency  not  only  to  small 
germs  but  to  large  kernels.  This  is  illustrated  by  Tables  23  and  24, 
which  give  the  average  weights  in  grams  of  the  air-dry  kernels  from 
twenty-eight  different  ears  which  were  used  in  1899  as  seed  for  high-fat 
and  low-fat  plots.   The  percentage  of  fat  in  the  dry  matter  is  also  given. 

The  average  weight  of  the  high-fat  kernels  is  .345  gram,  while  the 


232 


Corn  No 

Fat,  per  cent. . 
Kernel,  av.  wt. 


BULLETIN    NO.    55. 

.  .    1338     1512 

.  6.08    3.64 

..     .335 310 


I  June, 


Figure  5. 

low-fat  kernels  average  .420  gram.     However,  there  are  wide  variations 
from  this  apparent  tendency. 


1889J  CHEMISTRY    OF    THE    CORN    KERNEL.  233 

TABLE  23.    Average  Weights  of  Kernels  from  twelve  Ears  of  High-fat  Corn. 


Ear  No. 

Corn 

Kernel. 

Fat, 

1 

Ear  No. 

Corn 

Kernel, 

Fat, 

No. 

ave.  wt. 

per  cent. 

No. 

ave.   wt. 

percent. 

I 

1413 

325 

5.83 

7 

1354 

295 

6.49 

2 

1342 

370 

5.90 

8 

1476 

400 

6.34 

3 

1338 

.335 

6.08 

9 

1308 

315 

6.09 

4 

1314 

345 

6.28 

10 

1276 

.405 

5.90 

5 

1389 

.305 

6.47 

II 

1379 

.340 

5.89 

6 

1352 

340 

6.71 

12 

1259 

.370 

5.82 

Genei 

al  average 

.345 

TABLE  24.     Average  Weights   of   Kernels   from   Sixteen   Ears   of   Low-fat 

Corn. 


Ear 

Corn 

Kernel, 

Fat. 

Ear 

Corn 

Kernel, 

Fat, 

No. 

No. 

ave.  wt. 

percent. 

No. 

No. 

ave.  wt. 

per  cent. 

I 

1521 

.490 

3-64 

9 

1522 

.525 

3.27 

2 

1559 

.430 

3.63 

10 

1531 

.380 

3-33 

3 

1564 

.500 

3.58 

II 

1545 

.470 

3.35 

4 

1538 

.370 

3.56 

12 

i486 

.430 

3.39 

5 

1504 

.390 

3.38 

13 

1557 

.500 

3.56 

6 

1539 

.355 

3.34 

M 

1543 

.410 

3.59 

7 

1516 

.390 

332 

15 

1512 

.310 

3.64 

8 

1529 

.320 

3.22 

16 

1548 

.450 

3.65 

General  Average 

.420 

While  the  tendency  of  high-fat  corn  to  small  kernels  and  of  low- 
fat  corn  to  large  kernels  aids,  in  a  way,  in  the  selection  of  corn  of  high 
or  low  fat  content,  the  difficulty  of  judging  the  percentage  of  fat  by 
the  comparative  sizes  of  germ  and  kernel  is  greatly  increased  by  the 
wide  variations  in  the  size  of  kernels.  With  kernels  of  approximately 
the  same  size,  and  with  germs  of  similar  shape,  as  those  shown  in  Figure 
4,  it  is  an  easy  matter  to  distinguish  between  high-fat  corn  and  low-fat 
corn;  but  frequently  a  large  kernel  of  low  fat  content  will  have  a  larger 
germ  than  a  smaller  kernel  of  a  higher  percentage  of  fat;  or  the  germs 
in  the  kernels  from  one  ear  may  be  short  and  thick,  and  from  another 
ear  they  may  be  long  and  slender,  the  difficulties  in  the  way  of  forming 
accurate  judgment  being  thus  increased. 

To  obtain  exact  data  as  to  the  relation  between  the  percentage  of 
fat  and  the  percentage  of  germ  in  the  corn  kernel,  the  germs  were  re- 
moved from  a  large  number  of  kernels,  the  weight  of  the  whole  kernel 
and  also  of  the  separated  germ  being  determined  and  reported  on  the 
basis    of    dry  matter,    having  been   dried   in    hydrogen   before    being 


234 


BULLETIN    NO.    55. 


Ifunej 


weighed.  It  was  found  that  after  soaking  corn  kernels  in  hot  water  for 
about  thirty  minutes  the  germs  are  easily  removed  in  the  entire  state 
and  quite  free  from  other  portions  of  the  kernel. 

In  Table  25  are  given  the  results  from  eighty  kernels  of  corn, 
ten  kernels  being  taken  from  each  of  eight  different  ears.  No.  1354 
represents  an  ear  of  high  fat  content,  6.49  per  cent.,  and  small 
kernels,  average  weight  .2652  gram.  The  germs  average  .0374  gram  in 
weight,  and  amount  to  14. 11  per  cent,  of  the  whole  kernel.  Corn  No. 
1564  contains  3.58  per  cent,  of  fat.  The  kernels  average  .4631  grara 
and  the  germs  .0421  gram  in  weight.  The  germs  amount  to  only  9.10 
per  cent,  of  the  whole  kernel  although  the  average  weight  of  the  gerra 
is  considerably  more  than  in  No.  1354.  This  ear,  No.  1564,  illustrates 
a  relatively  low  fat  content  produced  by  an  absolute  increase  in  car- 
bohydrates. In  corn  No.  1352,  containing  6.71  per  cent,  fat  and  No. 
1529,  containing  3.22  per  cent,  fat,  the  kernels  are  approximately  uni- 
form in  size,  the  former  being  .3013  and  the  latter  .3181  gram  in 
average  weight.     The  germs  in  the  high-fat  ear  amount  to  12.40  per 

TABLE  25.     Weights  of  Corn  Kernels  with  Weight  and  Percentage  of  Germ. 


Kernel 

No 


Kernel, 
wt.  gms. 


Germ, 
wt.  gms. 


Germ, 
per  cent. 


Corn  No 

.  1-354. —  Fat  =  6.49 

per  cent. 

I 

.2611 

.0411 

15.74 

2 

.2718 

.0385 

14.16 

3 

•  2633 

.0370 

14.05 

4 

.2789 

.0382 

13.70 

5 

.2427 

■  0347 

14.30 

6 

.2859 

.0372 

13.01 

7 

.2642 

.0362 

13.70 

8 

.2595 

.0329 

12.68 

9 

.2567 

•  0359 

13.99 

10 

.2680 

.0422 

15.75 

Averages, 

.2652 

.0374 

14.11 

Corn  No,  1352.  — Fat  ^  6.71  percent. 


I 
2 
3 
4 
5 
6 

7 
8 

9 
10 


Averages, 


.3113 
.2872 
.2864 
.2821 
.2667 

■  3694 
•3434 
.2682 
.3116 
.2870 

•  3013 


.0391 
.0360 
.0340 

•0374 
.0360 
.0442 
.0414 
.0300 
.0402 
.0348 

•0373 


12.56 
12.53 
11.87 
13.26 
13.50 
11.97 
12.06 
11.18 
12.90 
12.13 

12.40 


Kernel 
No. 


Kernel, 
wt.  gms. 


Germ, 
wt.  gms. 


Germ, 
per  cent. 


Corn  No.  1564.  —  Fat=3.58  percent 


I 

.4478 

.0418 

9.33 

2 

.4428 

.0446 

10.07 

3 

.4402 

.0402 

9.13 

4 

•4943 

.0420 

8.50 

5 

.4205 

.0405 

9  63 

6 

•  4714 

•0439 

9.31 

7 

.4968 

.0436 

8.78 

8 

.4398 

.0361 

8.21 

9 

.4581 

.0446 

9.74 

10 

.5188 

.0432 

8  33 

Averages, 

.4631 

.0421 

9.10 

Corn  No.  1529. —  Fat  =  3. 22  percent. 


I 
2 
3 
4 
5 
6 

7 
8 

9 
10 

Averages. 


•  2859 
.2882 
•3533 

•  3135 
•3277 
.3417 
.2918 

.3178 
•3273 
.3338 

-3181 


.0250 
.0237 
.0297 
.0265 
.0273 
.0310 
•0257 
.0276 
.027S 
.0280 


.0272 


8  74 
8.22 
8.41 
8.45 
8.33 
9.07 
8.81 
8.68 
8.49 
8.39 

8.56 


1899-] 


CHEMISTRY  OF  THE  CORN  KERNEL. 


235 


TABLE  25. — Conthiued. 


Kernel       Kernel, 
No.         wt.  gras. 


Germ, 
wt.  gms. 


Germ, 
per  cent. 


Corn  No.  1338.  —  Fat  =  6.08  per  cent. 


I 

.3268 

•0373 

11.41 

2 

.3229 

.0385 

11.92 

3 

.3031 

.0308 

10.16 

4 

.3122 

.0400 

12.81 

5 

■3025 

.0349 

11.54 

6 

.3018 

.0384 

12.72 

7 

.2963 

•  0363 

12.25 

8 

•  3095 

.0361 

11.66 

9 

.2871 

.0395 

13.76 

10 

.3424 

.0407 

11.89 

Averages 

.3105 

•0373 

12.01 

Corn  No.  1259. —  Fat  =:  5  82  per  cent. 


I 

2719 

2 

3172 

3 

4 
5 
6 

3571 
3602 

3446 
3786 

7 
8 

3453 
3206 

9 

3927 

10 

3304 

Averages 

3419 

•  0371 
.0390 
.0468 
.0514 

.0482 

•  0455 
.0450 

•  0454 
.0472 
.0476 


•0453 


13.64 
12  30 
13.11 
14.27 
13.99 
12.02 
13.03 
14.16 
12.02 
14.41 


13.30 


Kernel 

No. 


Kernel, 
wt.  gras. 


Germ, 
wt.  gms. 


Germ, 
per  cent. 


Corn  No.  1512. —  Fat  =  3  64  per  cent. 


I 
2 
3 

4 
5 
6 

7 

8 

9 
10 


Averages 


.2813 
.3156 

■  2674 
.2740 
.2805 

■  2935 
.3223 

•  2752 
.3008 
.2664 


.2877 


.0258 
.0259 
.0206 
.0229 
.0250 
.0232 
.0251 
.0238 
.0233 
.0222 


.0238 


9.17 
8.21 
7.70 
8.36 
8.91 
7.90 
7.79 
8.65 
7.75 
8.33 


8.28 


Corn  No.  1516. —  Fat  =  3.32  per  cent. 


I 
2 
3 
4 
5 
6 

7 
8 

9 

ID 


Averages 


•  3969 

•  3293 
.3586 

.3434 

•  3401 

.3348 

■  3317 
.3096 

.3843 

•  3733 


.3502 


.0338 
.0246 
.0364 
.0318 
.0296 
.0283 
.0272 
.0240 
.0340 
.0373 


.0307 


8.52 
7.47 
10.15 
9.26 
8.70 
8.45 
8.20 
7.75 
8.85 
9.99 


8.73 


£ent.  of  the  whole  kernels,  and  to  only  8.56  per  cent,  in  the  low-fat 
ear.  This  difference  is  due  to  the  absolute  difference  in  the  size  of  the 
jgerms,  the  germs  from  the  high-fat  kernels  being  .0373  gram  and  from 
ihe  low-fat  kernels  only  .0272  gram  average  weight.  Nos.  1338  and 
15 12  are  the  same  ears  as  are  shown  in  Figure  5,  and  from  which  the 
kernels  shown  in  Figure  4  were  taken.  The  fat  content  is  6.08  and  3.64 
per  cent,  and  the  percentage  of  germ  12.01  and  8.28,  respectively. 
Nos.  1259  and  15 16  are  ears  with  medium  sized  kernels,  the  average 
weight  being  about  the  same  from  each  ear.  The  former  contains  5.82 
per  cent,  of  fat  and  13.30  per  cent,  of  germ,  the  latter  3.32  per  cent,  of 
fat  and  8.73  per  cent,  of  germ,  as  an  average. 

It  will  be  seen  that  the  general  relation  between  the  percentage  of 
fat  and  the  percentage  of  germ  in  the  corn  kernel  is  clearly  established. 
■Of  course  there  are  minor  individual  differences  among  the  kernels 
-from  the  same  ear,  and  it  is  also  noted  that  there  is  a  difference  in  dif- 
ferent ears   as  to   the  relation  between  fat  content  and  germ  content. 


236 


BULLETIN    NO.    55. 


[June, 


For  example,  corn  No.  1354  contains  6.49  per  cent,  of  fat  and  14. 11 
per  cent,  of  germ;  while  corn  No.  1352  contains  a  higher  percentage  of 
fat  but  a  lower  percentage  of  germ.  Again  the  corn  of  lowest  fat  con- 
tent is  not  quite  the  lowest  in  percentage  of  germ.  These  minor  differ- 
ences are  perhaps  due  in  part,  to  the  varying  percentage  of  fat  in  the 
remainder  of  the  kernel,  although  the  variation  in  the  percentage  of  fat 
in  the  germ  is  doubtless  the  chief  factor  in  producing  such  differences. 
For  example,  Voorhees  found  26.65  P^^  cent,  of  fat  in  the  germs 
of  the  corn  kernel,  while  Balland  found  39.85  percent.  (See  Bulletin 
No.  53,  page  140). 

The  method  of  selecting  corn  of  high  or  low  fat  content  by  mechan- 
ical examination  is  similar  to  that  described  under  the  work  on  the 
protein  content  of  the  corn  kernel,  excepting  that  the  size  of  the  germ 
alone  as  compared  with  the  remainder  of  the  kernel  is  considered. 
Judgment  is  formed  by  examining  with  the  naked  eye  the  cross  sections 
and  longitudinal  sections  of  a  few  kernels  from  an  ear. 

Table  26  shows  the  results  obtained  in  picking  out  corn  by  mechan- 
ical examination  from  a  lot  which  contained  corn  of  only  very  high  or 
of  very  low  fat  content. 

TABLE  26.     Actual  Fat  Content  of  Corn  Separated  by  Mechanical 

Examination. 


Corn  selected  for 

Ear 

No. 

Corn  selected  for 

Ear 

No. 

Corn  selected  for 

Ear 

No. 

High  fat. 

Low  fat. 

High  fat. 

Low  fat. 

High  fat. 

Low  fat. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

I 
2 
3 
4 
5 

5.90 
6.08 
6.28 
3.65 
6.47 

3.56 
3.59 
3.63 
3.58 
3.32 

6 

7 

8 

9 
10 

6.71 
6.49 
5.94 
5.87 
6.34 

3.65 
3.22 
3.67 
3.27 
3.39 

II 

12 
13 
14 
15 

5.80 
6.09 
5.82 
5.90 
5.89 

3.67 
3.50 
3.63 
3.64 
3.64 

In  picking  out  fifteen  ears  for  high-fat  corn  and  fifteen  ears  for 
low-fat  corn  but  one  error  was  made,  namely,  the  fourth  ear  selected 
for  high-fat  corn  which  really  contained  a  low  percentage  of  fat. 

To  make  a  more  practical  test  of  the  method  a  miscellaneous  lot 
of  corn  was  examined, — in  all  two  hundred  seventy-two  ears,  which 
varied  in  fat  content  from  about  3.60  to  5.80  per  cent.  Twelve  ears  of 
very  high  fat  content  and  sixteen  ears  of  very  low  fat  content  had  been 
taken  from  this  lot  and  used  for  seed  in  1899  (see  Tables  23  and  24), 
otherwise  the  results  would  no  doubt  have  been  more  marked  than 
they  are. 

From    the    lot    of  two  hundred    seventy-two  ears,   by    mechanical 


1899] 


CHEMISTRY  OF  THE  CORN  KERNEL. 


237 


examination  eighteen  ears  were  selected  which  appeared  to  possess  a 
comparatively  high  fat  content,  and  at  the  same  time  thirty  ears  appar- 
ently low  in  fat  were  selected.     Tables  27  and  28  give  the  results. 


TABLE  27. 


Fat  Content  of  eighteen  Ears  selected  by  Mechanical 
Examination  for  High-fat  Corn. 


Ear 

No. 

Fat, 
per  cent. 

Ear 

No. 

Fat, 
per  cent. 

Ear 

No. 

Fat, 
per  cent. 

Ear 

No. 

Fat, 
per  cent. 

Ear 

No. 

Fat, 
per  cent. 

I 
2 
3 
4 

4.94 
4.30 
5.43 
5.64 

5 
6 

7 

8 

5.23 
5.58 
5.06 
5.26 

9 
10 
11 
12 

5.22 
5.33 
5.55 
4.99 

13 

14 

15 
16 

5.27 
5.12 
5.73 
5.43 

17 
18 

4.97 
5.21 

i 

Werace 

5.24 

TABLE  28.     Fat  Content  of  thirty  Ears  selected  by  Mechanical  Examina- 
tion for  Low  Fat  Corn. 


Ear 

Fat, 

Ear 

Fat, 

Ear 

Fat, 

Ear 

Fat, 

Ear 

Fat, 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

No. 

per  cent. 

I 

4.01 

7 

4.07 

13 

3.73 

19 

4.52 

25 

4.09 

2 

4.11 

8 

4.20 

14 

3.76 

20 

4.29 

26 

4.27 

3 

3.64 

9 

3.91 

15 

5.21 

21 

3.81 

27 

4.02 

4 

3.67 

10 

4.85 

16 

3.63 

22 

4.39 

28 

3.87 

5 

4.52 

II 

4.35 

17 

4.02 

23 

4.43 

29 

4.00 

6 

3.66 

12 

4.52 

18 

4.55 

24 

3.80 

30 

3.98 

1 

Average 

4.13 

The  average   fat   content  of  the  ears  selected  for  high-fat  corn  is 
5.24  per  cent.,  while  4. 13  is  the  average  of  that  selected  for  low-fat  corn. 

TABLE  29.     Weight  of  Corn  Kernels  with  Weight  and  Percentage  of  Germ. 


Ear  2.     Table  27.— 

Fat  =  4  30 

per  cent. 

Ear  15.     Table  28.— 

Fat  =  5  21  per  cent. 

Kernel 

Kernel, 

Germ, 

Germ, 

Kernel 

Kernel, 

Germ, 

Germ, 

No. 

wt.  gms. 

wt.  gms. 

per  cent. 

No. 

wt.  gms. 

wt.  gms. 

per  cent. 

I 

•  3580 

.0346 

9.66 

I 

.4014 

.0450 

11.21 

2 

.3670 

.0362 

9.86 

2 

•  3674 

.0348 

9.47 

3 

•  2939 

.0277 

9.42 

3 

■3975 

.0463 

11.65 

4 

.2841 

.0306 

10.77 

4 

•4392 

.0410 

9.33 

5 

.2969 

.0262 

8.82 

5 

•4571 

.0539 

11.79 

6 

■  3054 

.0326 

10.67 

6 

•  3541 

.0442 

12.48 

7 

•  3156 

.0304 

9.63 

7 

.3968 

.0377 

9.50 

8 

.2866 

.0284 

9.91 

8 

.4225 

.0463 

10.96 

9 

•  3452 

.0354 

10.25 

9 

.3850 

.0497 

12.91 

10 

.3053 

.0280 

9.17 

10 

.4096 

.0464 

11.33 

Averages 

•3158 

.0310 

9.82 

Averages 

•  4031 

.0445 

11.06 

238  BULLETIN    NO.    55.  l/une, 

If  we  omit  ear  No.  2  in  Table  27  and  ear  No.  15  in  Table  28, 
the  lowest  percentage  of  fat  in  the  ears  selected  for  high  fat  content  is 
higher  than  the  highest  percentage  in  the  low-fat  selection. 

Ten  kernels  from  each  of  the  two  ears  just  mentioned  were  taken, 
and  the  exact  percentage  of  germ  in  each  kernel  determined,  in  order 
to  ascertain  whether  these  ears  were  selected  because  of  incorrect  judg- 
ment or  were  exceptions  to  the  general  rule  that  the  percentage  of  fat 
varies  with  the  percentage  of  germ  in  the  corn  kernel.  The  results  are 
given  in  Table  29. 

While  some  variations  in  individual  kernels  from  the  same  ear 
exist,  it  is  seen  that  the  corn  of  4.30  per  cent,  fat  contains  9.82  per 
cent,  of  germ,  while  the  ear  with  5.21  per  cent  fat  contains  11.06  per 
cent,  of  germ,  in  the  kernel  as  an  average,  showing  that  the  judgment 
was  incorrect,  having  been  formed  possibly  from  insufficient  data. 

SUMMARY  OF  EXPERIMENTS  TO  IMPROVE  THE  CHEMICAL 
COMPOSITION  OF  THE  CORN  KERNEL. 

All  results  thus  far  obtained  indicate  that  it  is  possible  to  influence 
the  composition  of  corn;  that  by  proper  selection  of  seed  any  of  its 
principal  constituents,  protein,  fat,  or  carbohydrates,  may  be  increased 
or  decreased. 

In  1897  a  plot  of  corn  planted  with  seed  containing  a  high  per- 
centage of  protein  produced  a  crop  containing  11. 10  per  cent,  of  pro- 
tein, while  10.55  was  the  percentage  contained  in  a  crop  grown  from 
seed  of  low  protein  content.  By  considering  only  the  central  half  of 
each  plot,  the  crop  from  seed  high  in  protein  shows  11. 12  per  cent,  of 
protein,  and  the  crop  from  low-protein  seed  shows  10.21  per  cent. 

In  1898  the  crop  of  corn  from  the  seed  of  high  protein  content 
contained  11.05  per  cent,  of  protein,  while  that  from  low-protein  seed 
contained  10.55  P^^"  cent.  If  only  the  central  half  of  each  plot  is 
considered  the  results  show  11. 17  per  cent,  and  10.47  P^r  cent,  of  pro- 
tein in  the  corn  from  the  respective  seed. 

The  average  protein  content  of  twenty-two  ears  of  corn  grown  in 
twenty-two  different  hills  from  high-protein  seed  was  11. 11  per  cent., 
while  10.15  was  the  average  percentage  of  protein  contained  in  twenty- 
two  other  ears  grown  in  the  same  twenty-two  hills  from  low-protein  seed. 

Fifty  hills  of  corn  were  planted  with  two  kernels  of  high-protein 
seed  and  two  kernels  of  low-protein  seed  in  each  hill.  The  average 
protein  content  of  the  crop  grown  from  high-protein  seed  was  11. 71 
per  cent.,  while  10.46  was  the  average  percentage  in  the  crop  from  the 
low-protein  seed. 

In  the  six  tests  the  selection  of  seed  corn  of  high  and  low  protein 


1899]  CHEMISTRY    OK    THE    CORN    KERNEL.  239 

content  has  produced  differences  in  the  crops  varying  from  .50  to  1.25  per 
cent,  of  protein. 

In  1897  a  plot  of  corn  planted  with  seed  of  high  fat  content  pro- 
duced a  crop  containing  4.73  per  cent,  of  fat,  while  the  crop  produced 
on  a  plot  planted  with  seed  of  low  fat  content  contained  an  average  of 
4.06  per  cent.  Considering  only  the  central  half  of  each  plot  the  crop 
from  the  high-fat  seed  contained  4.82  per  cent,  of  fat,  while  that  from 
low-fat  seed  contained  4.03  per  cent. 

In  1898  the  high-fat  seed  produced  a  crop  containing  5.15  per 
cent,  of  fat  and  the  crop  from  low-fat  seed  contained  only  3.99  per 
cent.  Again  by  considering  only  the  central  half  of  each  plot  the  per- 
centages of  fat  in  the  crops  are  found  to  be  5.29  and  3.84,  respectively. 

The  average  fat  content  of  twenty-seven  ears  grown  in  1898  in 
twenty-seven  different  hills  from  high-fat  seed  was  5.06  per  cent.,  while 
4.01  was  the  average  percentage  of  fat  contained  in  twenty-seven  other 
ears  grown  in  the  same  twenty-seven  hills  from  seed  of  low  fat  content. 

Fifty  hills  were  planted  with  two  kernels  of  high-fat  seed  and  two 
kernels  of  low--fat  seed  in  each  hill.  The  average  fat  content  of  the 
crop  produced  from  the  high-fat  seed  was  5.08  per  cent.,  while  3.97 
was  the  average  percentage  in  the  crop  from  low-fat  seed. 

In  the  six  tests  the  selection  of  seed  of  high  and  low  fat  content 
has  produced  differences  in  the  crops  varying  from  .67  to  1.45  percent, 
of  fat. 

The  fat  content  of  corn  is  even  more  susceptible  to  the  influence  of 
seed  selection  than  is  the  protein  content,  doubtless  due  to  the  fact  that 
the  primary  materials  from  which  fat  is  manufactured,  namely,  carbon 
dioxid  and  water,  are  usually  furnished  to  the  plant  in  unlimited  supply, 
while  the  formation  of  protein  is  essentially  dependent  upon  the  supply 
of  available  nitrogen  in  the  soil. 

As  the  percentage  of  carbohydrates  (principally  starch  in  corn) 
varies  inversely  with  the  combined  percentages  of  protein  and  fat  it 
follows  that  the  carbohydrates  are  increased  in  percentage  whenever  the 
combined  percentage  of  protein  and  fat  is  decreased,  and  vice  versa. 

It  has  been  found  that  the  protein  content  of  corn  varies  chiefly 
with  the  proportion  of  glutenous  layer  in  the  kernel  and  that  by 
mechanical  examination  of  corn  kernels  this  variation  in  the  propor- 
tion of  glutenous  layer  can  easily  be  observed  with  the  naked  eye. 

It  has  also  been  found  that  the  fat  content  of  corn  varies  quite 
uniformly  with  the  proportion  of  germ  in  the  kernel  and  that  by  mechan- 
ical examination  this  variation  in  the  relative  amount  of  germ  in  the 
whole  kernel  can  also  be  observed  with  the  eye. 

By  actual  trial  it  has  been  found   both  possible  and  practicable  to 


240  BULLETIN    NO.     55.  \^June,    1S99. 

select  corn  by  mechanical  examination  with  either  high  or  low  content 
of  protein,  fat,  or  starch. 

While  further  investigations  are  necessary,  and  are  in  progress,  to 
determine  more  accurately  the  best  methods  and  more  definitely  the 
possibilities  of  improvement  in  the  chemical  composition  of  corn,  it  is 
here  stated,  tentatively,  that  essentially  by  the  methods  reported  in  this 
bulletin  any  corn  grower  will  be  able  to  select  seed  and  to  breed  corn  to 
increase  or  to  decrease  the  percentage  of  any  one  of  its  three  principal 
chemical  constituents. 

All  experiments  reported  in  this  bulletin  have  been  carried  on  with 
the  one  variety  of  corn,  namely,  Burr's  White.  Of  course,  it  is  not 
believed  that  Burr's  White  is  the  best  variety  for  improvement  in  corn 
in  every  one  of  the  several  important  lines.  Indeed  it  seems  highly 
probable  that  one  variety  of  corn  will  be  found  best  adapted  to  but  one 
line  of  improvement.  We  have  in  progress  chemical  studies  of  other 
varieties  of  corn,  and  a  considerable  amount  of  data  and  information 
has  been  already  acquired,  but  it  is  reserved,  pending  further  investiga- 
tions, for  future  publication,  the  special  object  of  this  bulletin  being 
to  give  the  data,  thus  far  obtained,  indicating  the  possibility  and  estab- 
lishing the  fact  that  the  corn  kernel  may  be  improved  in  chemical 
composition. 

It  may  be  stated  that  improvement  in  the  composition  of  other 
parts  of  the  corn  plant  is  under  consideration  by  this  Station.  Plans  are 
made  also  to  investigate  other  questions  relating  to  this  general  subject  ; 
such  as  the  effect  of  changes  in  the  chemical  composition  of  corn 
upon  its  digestibility,  vitality,  yield,  etc. 

The  results  obtained  in  our  investigations  to  improve  the  compo- 
sition of  corn  have  suggested  the  possibility  of  improving  other  grains 
by  somewhat  similar  methods.  It  seems  not  improbable  that  the  differ- 
ent grains  or  kernels  produced  in  a  single  head  of  wheat,  oats,  barley, 
etc.,  may  be  found  to  be  approximately  uniform  in  composition.  If 
so,  a  method  is  thus  offered  for  selecting  seed  according  to  its  chemical 
composition. 

CYRIL  GEORGE  HOPKINS,   M.S.,   Ph.D., 

Chemist. 


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